Replace some string16's with base namespace in chrome/browser

TBR=sky

Review URL: https://codereview.chromium.org/101953005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240126 0039d316-1c4b-4281-b951-d872f2087c98

245 files changed, 891 insertions, 847 deletions

diff --git a/chrome/browser/ui/android/autofill/autofill_dialog_controller_android.cc b/chrome/browser/ui/android/autofill/autofill_dialog_controller_android.cc
index 96dcadeb..fabac80a 100644
--- a/chrome/browser/ui/android/autofill/autofill_dialog_controller_android.cc
+++ b/chrome/browser/ui/android/autofill/autofill_dialog_controller_android.cc
@@ -346,11 +346,12 @@ void AutofillDialogControllerAndroid::DialogContinue(
     jstring jlast_used_billing,
     jstring jlast_used_shipping,
     jstring jlast_used_card) {
-  const string16 email = AutofillDialogResult::GetWalletEmail(env, wallet);
+  const base::string16 email =
+      AutofillDialogResult::GetWalletEmail(env, wallet);
   const std::string google_transaction_id =
       AutofillDialogResult::GetWalletGoogleTransactionId(env, wallet);
 
-  const string16 last_used_account_name =
+  const base::string16 last_used_account_name =
       base::android::ConvertJavaStringToUTF16(env, jlast_used_account_name);
   const std::string last_used_billing =
       base::android::ConvertJavaStringToUTF8(env, jlast_used_billing);
diff --git a/chrome/browser/ui/android/chrome_http_auth_handler.cc b/chrome/browser/ui/android/chrome_http_auth_handler.cc
index 300a6ea..fd85d9a 100644
--- a/chrome/browser/ui/android/chrome_http_auth_handler.cc
+++ b/chrome/browser/ui/android/chrome_http_auth_handler.cc
@@ -21,7 +21,7 @@ using base::android::ConvertJavaStringToUTF16;
 using base::android::ConvertUTF16ToJavaString;
 using base::android::ScopedJavaLocalRef;
 
-ChromeHttpAuthHandler::ChromeHttpAuthHandler(const string16& explanation)
+ChromeHttpAuthHandler::ChromeHttpAuthHandler(const base::string16& explanation)
     : observer_(NULL),
       explanation_(explanation) {
 }
@@ -43,8 +43,9 @@ jobject ChromeHttpAuthHandler::GetJavaObject() {
   return java_chrome_http_auth_handler_.obj();
 }
 
-void ChromeHttpAuthHandler::OnAutofillDataAvailable(const string16& username,
-                                                    const string16& password) {
+void ChromeHttpAuthHandler::OnAutofillDataAvailable(
+    const base::string16& username,
+    const base::string16& password) {
   DCHECK(java_chrome_http_auth_handler_.obj() != NULL);
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jstring> j_username =
@@ -61,8 +62,8 @@ void ChromeHttpAuthHandler::SetAuth(JNIEnv* env,
                                     jstring username,
                                     jstring password) {
   if (observer_) {
-    string16 username16 = ConvertJavaStringToUTF16(env, username);
-    string16 password16 = ConvertJavaStringToUTF16(env, password);
+    base::string16 username16 = ConvertJavaStringToUTF16(env, username);
+    base::string16 password16 = ConvertJavaStringToUTF16(env, password);
     observer_->SetAuth(username16, password16);
   }
 }
diff --git a/chrome/browser/ui/android/chrome_http_auth_handler.h b/chrome/browser/ui/android/chrome_http_auth_handler.h
index 9b46083..b5c52c7 100644
--- a/chrome/browser/ui/android/chrome_http_auth_handler.h
+++ b/chrome/browser/ui/android/chrome_http_auth_handler.h
@@ -17,7 +17,7 @@
 // by, e.g., showing the user a login dialog.
 class ChromeHttpAuthHandler {
  public:
-  ChromeHttpAuthHandler(const string16& explanation);
+  ChromeHttpAuthHandler(const base::string16& explanation);
   ~ChromeHttpAuthHandler();
 
   // This must be called before using the object.
@@ -35,8 +35,8 @@ class ChromeHttpAuthHandler {
 
   // Forwards the autofill data to the Java land object.
   void OnAutofillDataAvailable(
-      const string16& username,
-      const string16& password);
+      const base::string16& username,
+      const base::string16& password);
 
   // --------------------------------------------------------------
   // JNI Methods
@@ -67,7 +67,7 @@ class ChromeHttpAuthHandler {
   LoginHandler* observer_;
   base::android::ScopedJavaGlobalRef<jobject> java_chrome_http_auth_handler_;
   // e.g. "The server example.com:80 requires a username and password."
-  string16 explanation_;
+  base::string16 explanation_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeHttpAuthHandler);
 };
diff --git a/chrome/browser/ui/android/content_settings/popup_blocked_infobar_delegate.h b/chrome/browser/ui/android/content_settings/popup_blocked_infobar_delegate.h
index 1bbbb79..66c98eb 100644
--- a/chrome/browser/ui/android/content_settings/popup_blocked_infobar_delegate.h
+++ b/chrome/browser/ui/android/content_settings/popup_blocked_infobar_delegate.h
@@ -23,9 +23,9 @@ class PopupBlockedInfoBarDelegate : public ConfirmInfoBarDelegate {
   // ConfirmInfoBarDelegate:
   virtual int GetIconID() const OVERRIDE;
   virtual PopupBlockedInfoBarDelegate* AsPopupBlockedInfoBarDelegate() OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
   virtual int GetButtons() const OVERRIDE;
-  virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
+  virtual base::string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
 
   int num_popups_;
diff --git a/chrome/browser/ui/android/infobars/auto_login_infobar_delegate_android.h b/chrome/browser/ui/android/infobars/auto_login_infobar_delegate_android.h
index 8d97b01..d84e7fc 100644
--- a/chrome/browser/ui/android/infobars/auto_login_infobar_delegate_android.h
+++ b/chrome/browser/ui/android/infobars/auto_login_infobar_delegate_android.h
@@ -17,7 +17,7 @@ class AutoLoginInfoBarDelegateAndroid : public AutoLoginInfoBarDelegate {
   // AutoLoginInfoBarDelegate:
   virtual bool Accept() OVERRIDE;
   virtual bool Cancel() OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
 
   // These methods are defined in downstream code.
   bool AttachAccount(JavaObjectWeakGlobalRef weak_java_translate_helper);
diff --git a/chrome/browser/ui/android/infobars/confirm_infobar.cc b/chrome/browser/ui/android/infobars/confirm_infobar.cc
index 48a3f14..b61d0c9 100644
--- a/chrome/browser/ui/android/infobars/confirm_infobar.cc
+++ b/chrome/browser/ui/android/infobars/confirm_infobar.cc
@@ -83,7 +83,7 @@ string16 ConfirmInfoBar::GetTextFor(
     ConfirmInfoBarDelegate::InfoBarButton button) {
   ConfirmInfoBarDelegate* delegate = GetDelegate();
   return (delegate->GetButtons() & button) ?
-      delegate->GetButtonLabel(button) : string16();
+      delegate->GetButtonLabel(button) : base::string16();
 }
 
 
diff --git a/chrome/browser/ui/android/infobars/confirm_infobar.h b/chrome/browser/ui/android/infobars/confirm_infobar.h
index 1156a02..a25da9e 100644
--- a/chrome/browser/ui/android/infobars/confirm_infobar.h
+++ b/chrome/browser/ui/android/infobars/confirm_infobar.h
@@ -24,7 +24,7 @@ class ConfirmInfoBar : public InfoBarAndroid {
                              const std::string& action_value) OVERRIDE;
 
   ConfirmInfoBarDelegate* GetDelegate();
-  string16 GetTextFor(ConfirmInfoBarDelegate::InfoBarButton button);
+  base::string16 GetTextFor(ConfirmInfoBarDelegate::InfoBarButton button);
 
   base::android::ScopedJavaGlobalRef<jobject> java_confirm_delegate_;
 
diff --git a/chrome/browser/ui/android/javascript_app_modal_dialog_android.cc b/chrome/browser/ui/android/javascript_app_modal_dialog_android.cc
index 2e15b99..5db966c 100644
--- a/chrome/browser/ui/android/javascript_app_modal_dialog_android.cc
+++ b/chrome/browser/ui/android/javascript_app_modal_dialog_android.cc
@@ -110,14 +110,15 @@ void JavascriptAppModalDialogAndroid::CloseAppModalDialog() {
 }
 
 void JavascriptAppModalDialogAndroid::AcceptAppModalDialog() {
-  string16 prompt_text;
+  base::string16 prompt_text;
   dialog_->OnAccept(prompt_text, false);
   delete this;
 }
 
 void JavascriptAppModalDialogAndroid::DidAcceptAppModalDialog(
     JNIEnv* env, jobject, jstring prompt, bool should_suppress_js_dialogs) {
-  string16 prompt_text = base::android::ConvertJavaStringToUTF16(env, prompt);
+  base::string16 prompt_text =
+      base::android::ConvertJavaStringToUTF16(env, prompt);
   dialog_->OnAccept(prompt_text, should_suppress_js_dialogs);
   delete this;
 }
diff --git a/chrome/browser/ui/android/login_prompt_android.cc b/chrome/browser/ui/android/login_prompt_android.cc
index 25a30a7..6048f68 100644
--- a/chrome/browser/ui/android/login_prompt_android.cc
+++ b/chrome/browser/ui/android/login_prompt_android.cc
@@ -28,8 +28,8 @@ class LoginHandlerAndroid : public LoginHandler {
   // LoginHandler methods:
 
   virtual void OnAutofillDataAvailable(
-      const string16& username,
-      const string16& password) OVERRIDE {
+      const base::string16& username,
+      const base::string16& password) OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     DCHECK(chrome_http_auth_handler_.get() != NULL);
     chrome_http_auth_handler_->OnAutofillDataAvailable(
@@ -39,7 +39,7 @@ class LoginHandlerAndroid : public LoginHandler {
 
   virtual void BuildViewForPasswordManager(
       PasswordManager* manager,
-      const string16& explanation) OVERRIDE {
+      const base::string16& explanation) OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
     // Get pointer to TabAndroid
diff --git a/chrome/browser/ui/android/simple_message_box_android.cc b/chrome/browser/ui/android/simple_message_box_android.cc
index 384a714..5700db7 100644
--- a/chrome/browser/ui/android/simple_message_box_android.cc
+++ b/chrome/browser/ui/android/simple_message_box_android.cc
@@ -9,8 +9,8 @@
 namespace chrome {
 
 MessageBoxResult ShowMessageBox(gfx::NativeWindow parent,
-                                const string16& title,
-                                const string16& message,
+                                const base::string16& title,
+                                const base::string16& message,
                                 MessageBoxType type) {
   NOTIMPLEMENTED();
   return MESSAGE_BOX_RESULT_NO;
diff --git a/chrome/browser/ui/android/tab_model/tab_model.h b/chrome/browser/ui/android/tab_model/tab_model.h
index 9f705ca..e00953e 100644
--- a/chrome/browser/ui/android/tab_model/tab_model.h
+++ b/chrome/browser/ui/android/tab_model/tab_model.h
@@ -63,14 +63,14 @@ class TabModel : public content::NotificationObserver,
   virtual void OpenClearBrowsingData() const = 0;
 
   // Returns search terms extracted from the current url if possible.
-  string16 GetSearchTermsForCurrentTab();
+  base::string16 GetSearchTermsForCurrentTab();
 
   // Returns the parameter that is used to trigger query extraction.
   std::string GetQueryExtractionParam();
 
   // Calls through to the ToolbarModel's GetCorpusNameForMobile -- see
   // comments in toolbar_model.h.
-  string16 GetCorpusNameForCurrentTab();
+  base::string16 GetCorpusNameForCurrentTab();
 
  protected:
   // Instructs the TabModel to broadcast a notification that all tabs are now
diff --git a/chrome/browser/ui/android/validation_message_bubble_android.cc b/chrome/browser/ui/android/validation_message_bubble_android.cc
index 7ea83a4..9b1af80 100644
--- a/chrome/browser/ui/android/validation_message_bubble_android.cc
+++ b/chrome/browser/ui/android/validation_message_bubble_android.cc
@@ -28,8 +28,8 @@ inline ContentViewCore* GetContentViewCoreFrom(RenderWidgetHost* widget_host) {
 ValidationMessageBubbleAndroid::ValidationMessageBubbleAndroid(
     RenderWidgetHost* widget_host,
     const gfx::Rect& anchor_in_root_view,
-    const string16& main_text,
-    const string16& sub_text) {
+    const base::string16& main_text,
+    const base::string16& sub_text) {
   JNIEnv* env = base::android::AttachCurrentThread();
   java_validation_message_bubble_.Reset(
       Java_ValidationMessageBubble_createAndShow(
@@ -70,8 +70,8 @@ namespace chrome {
 scoped_ptr<ValidationMessageBubble> ValidationMessageBubble::CreateAndShow(
     RenderWidgetHost* widget_host,
     const gfx::Rect& anchor_in_root_view,
-    const string16& main_text,
-    const string16& sub_text) {
+    const base::string16& main_text,
+    const base::string16& sub_text) {
   return scoped_ptr<ValidationMessageBubble>(new ValidationMessageBubbleAndroid(
       widget_host, anchor_in_root_view, main_text, sub_text)).Pass();
 }
diff --git a/chrome/browser/ui/android/validation_message_bubble_android.h b/chrome/browser/ui/android/validation_message_bubble_android.h
index ea6ed3c..6997483 100644
--- a/chrome/browser/ui/android/validation_message_bubble_android.h
+++ b/chrome/browser/ui/android/validation_message_bubble_android.h
@@ -25,8 +25,8 @@ class ValidationMessageBubbleAndroid : public chrome::ValidationMessageBubble {
  public:
   ValidationMessageBubbleAndroid(content::RenderWidgetHost* widget_host,
                                  const gfx::Rect& anchor_in_screen,
-                                 const string16& main_text,
-                                 const string16& sub_text);
+                                 const base::string16& main_text,
+                                 const base::string16& sub_text);
   virtual ~ValidationMessageBubbleAndroid();
   virtual void SetPositionRelativeToAnchor(
       content::RenderWidgetHost* widget_host,
diff --git a/chrome/browser/ui/android/website_settings_popup_android.cc b/chrome/browser/ui/android/website_settings_popup_android.cc
index 8eebb5b..9c1b161 100644
--- a/chrome/browser/ui/android/website_settings_popup_android.cc
+++ b/chrome/browser/ui/android/website_settings_popup_android.cc
@@ -126,7 +126,7 @@ void WebsiteSettingsPopupAndroid::SetIdentityInfo(
     Java_WebsiteSettingsPopup_addSection(env, popup_jobject_.obj(), icon_id,
         ConvertUTF8ToJavaString(env, headline).obj(), description.obj());
 
-    string16 certificate_label =
+    base::string16 certificate_label =
         l10n_util::GetStringUTF16(IDS_PAGEINFO_CERT_INFO_BUTTON);
     if (!certificate_label.empty()) {
       Java_WebsiteSettingsPopup_setCertificateViewer(env, popup_jobject_.obj(),
@@ -172,7 +172,7 @@ void WebsiteSettingsPopupAndroid::SetSelectedTab(
 }
 
 void WebsiteSettingsPopupAndroid::SetFirstVisit(
-    const string16& first_visit) {
+    const base::string16& first_visit) {
   NOTIMPLEMENTED();
 }
 
diff --git a/chrome/browser/ui/android/website_settings_popup_android.h b/chrome/browser/ui/android/website_settings_popup_android.h
index 2edbe626..ea9e5b2 100644
--- a/chrome/browser/ui/android/website_settings_popup_android.h
+++ b/chrome/browser/ui/android/website_settings_popup_android.h
@@ -32,7 +32,7 @@ class WebsiteSettingsPopupAndroid : public WebsiteSettingsUI {
   virtual void SetPermissionInfo(
       const PermissionInfoList& permission_info_list) OVERRIDE;
   virtual void SetIdentityInfo(const IdentityInfo& identity_info) OVERRIDE;
-  virtual void SetFirstVisit(const string16& first_visit) OVERRIDE;
+  virtual void SetFirstVisit(const base::string16& first_visit) OVERRIDE;
   virtual void SetSelectedTab(WebsiteSettingsUI::TabId tab_id) OVERRIDE;
 
   static bool RegisterWebsiteSettingsPopupAndroid(JNIEnv* env);
diff --git a/chrome/browser/ui/app_list/app_context_menu.cc b/chrome/browser/ui/app_list/app_context_menu.cc
index 4fbaee3..d22e236 100644
--- a/chrome/browser/ui/app_list/app_context_menu.cc
+++ b/chrome/browser/ui/app_list/app_context_menu.cc
@@ -92,10 +92,10 @@ ui::MenuModel* AppContextMenu::GetMenuModel() {
         base::Bind(MenuItemHasLauncherContext)));
 
     if (!is_platform_app_)
-      menu_model_->AddItem(LAUNCH_NEW, string16());
+      menu_model_->AddItem(LAUNCH_NEW, base::string16());
 
     int index = 0;
-    extension_menu_items_->AppendExtensionItems(app_id_, string16(),
+    extension_menu_items_->AppendExtensionItems(app_id_, base::string16(),
                                                 &index);
 
     // Show Pin/Unpin option if shelf is available.
@@ -181,7 +181,7 @@ string16 AppContextMenu::GetLabelForCommandId(int command_id) const {
         l10n_util::GetStringUTF16(IDS_APP_LIST_CONTEXT_MENU_NEW_WINDOW);
   } else {
     NOTREACHED();
-    return string16();
+    return base::string16();
   }
 }
 
diff --git a/chrome/browser/ui/app_list/app_context_menu.h b/chrome/browser/ui/app_list/app_context_menu.h
index 7406c23..2dc3d89 100644
--- a/chrome/browser/ui/app_list/app_context_menu.h
+++ b/chrome/browser/ui/app_list/app_context_menu.h
@@ -38,7 +38,7 @@ class AppContextMenu : public ui::SimpleMenuModel::Delegate {
  private:
   // ui::SimpleMenuModel::Delegate overrides:
   virtual bool IsItemForCommandIdDynamic(int command_id) const OVERRIDE;
-  virtual string16 GetLabelForCommandId(int command_id) const OVERRIDE;
+  virtual base::string16 GetLabelForCommandId(int command_id) const OVERRIDE;
   virtual bool IsCommandIdChecked(int command_id) const OVERRIDE;
   virtual bool IsCommandIdEnabled(int command_id) const OVERRIDE;
   virtual bool GetAcceleratorForCommandId(
diff --git a/chrome/browser/ui/app_list/app_list_controller_browsertest.cc b/chrome/browser/ui/app_list/app_list_controller_browsertest.cc
index 7aad320..d61e9b0 100644
--- a/chrome/browser/ui/app_list/app_list_controller_browsertest.cc
+++ b/chrome/browser/ui/app_list/app_list_controller_browsertest.cc
@@ -67,7 +67,7 @@ class AppListControllerBrowserTest : public InProcessBrowserTest {
         temp_profile_dir,
         base::Bind(&AppListControllerBrowserTest::OnProfileCreated,
                    this),
-        string16(), string16(), std::string());
+        base::string16(), base::string16(), std::string());
     content::RunMessageLoop();  // Will stop in OnProfileCreated().
   }
 
diff --git a/chrome/browser/ui/app_list/chrome_signin_delegate.h b/chrome/browser/ui/app_list/chrome_signin_delegate.h
index 71e9a62..4f263ec 100644
--- a/chrome/browser/ui/app_list/chrome_signin_delegate.h
+++ b/chrome/browser/ui/app_list/chrome_signin_delegate.h
@@ -23,11 +23,11 @@ class ChromeSigninDelegate : public app_list::SigninDelegate {
   virtual void ShowSignin() OVERRIDE;
   virtual void OpenLearnMore() OVERRIDE;
   virtual void OpenSettings() OVERRIDE;
-  virtual string16 GetSigninHeading() OVERRIDE;
-  virtual string16 GetSigninText() OVERRIDE;
-  virtual string16 GetSigninButtonText() OVERRIDE;
-  virtual string16 GetLearnMoreLinkText() OVERRIDE;
-  virtual string16 GetSettingsLinkText() OVERRIDE;
+  virtual base::string16 GetSigninHeading() OVERRIDE;
+  virtual base::string16 GetSigninText() OVERRIDE;
+  virtual base::string16 GetSigninButtonText() OVERRIDE;
+  virtual base::string16 GetLearnMoreLinkText() OVERRIDE;
+  virtual base::string16 GetSettingsLinkText() OVERRIDE;
 
   Profile* profile_;
 
diff --git a/chrome/browser/ui/app_list/search/app_search_provider.cc b/chrome/browser/ui/app_list/search/app_search_provider.cc
index c7fc5f0..329455e 100644
--- a/chrome/browser/ui/app_list/search/app_search_provider.cc
+++ b/chrome/browser/ui/app_list/search/app_search_provider.cc
@@ -52,7 +52,7 @@ AppSearchProvider::AppSearchProvider(
 
 AppSearchProvider::~AppSearchProvider() {}
 
-void AppSearchProvider::Start(const string16& query) {
+void AppSearchProvider::Start(const base::string16& query) {
   const TokenizedString query_terms(query);
 
   ClearResults();
diff --git a/chrome/browser/ui/app_list/search/common/webservice_search_provider.cc b/chrome/browser/ui/app_list/search/common/webservice_search_provider.cc
index 2b77874..d3fb5b1 100644
--- a/chrome/browser/ui/app_list/search/common/webservice_search_provider.cc
+++ b/chrome/browser/ui/app_list/search/common/webservice_search_provider.cc
@@ -44,7 +44,7 @@ void WebserviceSearchProvider::StartThrottledQuery(
   last_keytyped_ = base::Time::Now();
 }
 
-bool WebserviceSearchProvider::IsValidQuery(const string16& query) {
+bool WebserviceSearchProvider::IsValidQuery(const base::string16& query) {
   // If |query| contains sensitive data, bail out and do not create the place
   // holder "search-web-store" result.
   if (IsSensitiveInput(query) ||
@@ -58,7 +58,7 @@ bool WebserviceSearchProvider::IsValidQuery(const string16& query) {
 
 // Returns whether or not the user's input string, |query|, might contain any
 // sensitive information, based purely on its value and not where it came from.
-bool WebserviceSearchProvider::IsSensitiveInput(const string16& query) {
+bool WebserviceSearchProvider::IsSensitiveInput(const base::string16& query) {
   const GURL query_as_url(query);
   if (!query_as_url.is_valid())
     return false;
diff --git a/chrome/browser/ui/app_list/search/common/webservice_search_provider.h b/chrome/browser/ui/app_list/search/common/webservice_search_provider.h
index 5aa45db..4e3ce06 100644
--- a/chrome/browser/ui/app_list/search/common/webservice_search_provider.h
+++ b/chrome/browser/ui/app_list/search/common/webservice_search_provider.h
@@ -25,7 +25,7 @@ class WebserviceSearchProvider : public SearchProvider {
   virtual ~WebserviceSearchProvider();
 
   // Validate the query for privacy and size.
-  bool IsValidQuery(const string16& query);
+  bool IsValidQuery(const base::string16& query);
 
   // Start a query with throttling enabled.
   void StartThrottledQuery(const base::Closure& start_query);
@@ -37,7 +37,7 @@ class WebserviceSearchProvider : public SearchProvider {
   WebserviceCache* cache_;  // BrowserContextKeyedService, not owned.
 
  private:
-  bool IsSensitiveInput(const string16& query);
+  bool IsSensitiveInput(const base::string16& query);
 
   // The timestamp when the last key event happened.
   base::Time last_keytyped_;
diff --git a/chrome/browser/ui/app_list/search/mixer_unittest.cc b/chrome/browser/ui/app_list/search/mixer_unittest.cc
index 7680ca0..98fa049 100644
--- a/chrome/browser/ui/app_list/search/mixer_unittest.cc
+++ b/chrome/browser/ui/app_list/search/mixer_unittest.cc
@@ -50,7 +50,7 @@ class TestSearchProvider : public SearchProvider {
   virtual ~TestSearchProvider() {}
 
   // SearchProvider overrides:
-  virtual void Start(const string16& query) OVERRIDE {
+  virtual void Start(const base::string16& query) OVERRIDE {
     ClearResults();
     for (size_t i = 0; i < count_; ++i) {
       const std::string id =
@@ -95,7 +95,7 @@ class MixerTest : public testing::Test {
   }
 
   void RunQuery() {
-    const string16 query;
+    const base::string16 query;
 
     for (size_t i = 0; i < providers_.size(); ++i) {
       providers_[i]->Start(query);
diff --git a/chrome/browser/ui/app_list/search/omnibox_provider.cc b/chrome/browser/ui/app_list/search/omnibox_provider.cc
index 18656b6..4ca991c 100644
--- a/chrome/browser/ui/app_list/search/omnibox_provider.cc
+++ b/chrome/browser/ui/app_list/search/omnibox_provider.cc
@@ -32,7 +32,7 @@ int ACMatchStyleToTagStyle(int styles) {
 
 // Translates ACMatchClassifications into SearchResult tags.
 void ACMatchClassificationsToTags(
-    const string16& text,
+    const base::string16& text,
     const ACMatchClassifications& text_classes,
     SearchResult::Tags* tags) {
   int tag_styles = SearchResult::Tag::NONE;
diff --git a/chrome/browser/ui/app_list/search/search_controller.cc b/chrome/browser/ui/app_list/search/search_controller.cc
index ce48663..2431e20 100644
--- a/chrome/browser/ui/app_list/search/search_controller.cc
+++ b/chrome/browser/ui/app_list/search/search_controller.cc
@@ -85,7 +85,7 @@ void SearchController::Init() {
 void SearchController::Start() {
   Stop();
 
-  string16 query;
+  base::string16 query;
   TrimWhitespace(search_box_->text(), TRIM_ALL, &query);
 
   dispatching_query_ = true;
diff --git a/chrome/browser/ui/app_list/search/term_break_iterator.cc b/chrome/browser/ui/app_list/search/term_break_iterator.cc
index 1349683..5c7d44d 100644
--- a/chrome/browser/ui/app_list/search/term_break_iterator.cc
+++ b/chrome/browser/ui/app_list/search/term_break_iterator.cc
@@ -11,7 +11,7 @@
 
 namespace app_list {
 
-TermBreakIterator::TermBreakIterator(const string16& word)
+TermBreakIterator::TermBreakIterator(const base::string16& word)
     : word_(word),
       prev_(npos),
       pos_(0),
@@ -48,7 +48,7 @@ bool TermBreakIterator::Advance() {
   return prev_ != pos_ || !iter_->end();
 }
 
-const string16 TermBreakIterator::GetCurrentTerm() const {
+const base::string16 TermBreakIterator::GetCurrentTerm() const {
   DCHECK(prev_ != npos && pos_ != npos);
   return word_.substr(prev_, pos_ - prev_);
 }
diff --git a/chrome/browser/ui/app_list/search/term_break_iterator.h b/chrome/browser/ui/app_list/search/term_break_iterator.h
index eb1bf6a..3a88cf9 100644
--- a/chrome/browser/ui/app_list/search/term_break_iterator.h
+++ b/chrome/browser/ui/app_list/search/term_break_iterator.h
@@ -26,7 +26,7 @@ namespace app_list {
 class TermBreakIterator {
  public:
   // Note that |word| must out live this iterator.
-  explicit TermBreakIterator(const string16& word);
+  explicit TermBreakIterator(const base::string16& word);
   ~TermBreakIterator();
 
   // Advance to the next term. Returns false if at the end of the word.
@@ -34,7 +34,7 @@ class TermBreakIterator {
 
   // Returns the current term, which is the substr of |word_| in range
   // [prev_, pos_).
-  const string16 GetCurrentTerm() const;
+  const base::string16 GetCurrentTerm() const;
 
   size_t prev() const { return prev_; }
   size_t pos() const { return pos_; }
@@ -54,7 +54,7 @@ class TermBreakIterator {
   // Returns new state for given |ch|.
   State GetNewState(char16 ch);
 
-  const string16& word_;
+  const base::string16& word_;
   size_t prev_;
   size_t pos_;
 
diff --git a/chrome/browser/ui/app_list/search/term_break_iterator_unittest.cc b/chrome/browser/ui/app_list/search/term_break_iterator_unittest.cc
index 05d0cc0..fbd298f 100644
--- a/chrome/browser/ui/app_list/search/term_break_iterator_unittest.cc
+++ b/chrome/browser/ui/app_list/search/term_break_iterator_unittest.cc
@@ -11,13 +11,13 @@ namespace app_list {
 namespace test {
 
 TEST(TermBreakIteratorTest, EmptyWord) {
-  string16 empty;
+  base::string16 empty;
   TermBreakIterator iter(empty);
   EXPECT_FALSE(iter.Advance());
 }
 
 TEST(TermBreakIteratorTest, Simple) {
-  string16 word(UTF8ToUTF16("simple"));
+  base::string16 word(UTF8ToUTF16("simple"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("simple"), iter.GetCurrentTerm());
@@ -25,7 +25,7 @@ TEST(TermBreakIteratorTest, Simple) {
 }
 
 TEST(TermBreakIteratorTest, CamelCase) {
-  string16 word(UTF8ToUTF16("CamelCase"));
+  base::string16 word(UTF8ToUTF16("CamelCase"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("Camel"), iter.GetCurrentTerm());
@@ -35,7 +35,7 @@ TEST(TermBreakIteratorTest, CamelCase) {
 }
 
 TEST(TermBreakIteratorTest, LowerToUpper) {
-  string16 word(UTF8ToUTF16("lowerToUpper"));
+  base::string16 word(UTF8ToUTF16("lowerToUpper"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("lower"), iter.GetCurrentTerm());
@@ -47,7 +47,7 @@ TEST(TermBreakIteratorTest, LowerToUpper) {
 }
 
 TEST(TermBreakIteratorTest, AlphaNumber) {
-  string16 word(UTF8ToUTF16("Chromium26.0.0.0"));
+  base::string16 word(UTF8ToUTF16("Chromium26.0.0.0"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("Chromium"), iter.GetCurrentTerm());
@@ -57,7 +57,7 @@ TEST(TermBreakIteratorTest, AlphaNumber) {
 }
 
 TEST(TermBreakIteratorTest, StartsWithNumber) {
-  string16 word(UTF8ToUTF16("123startWithNumber"));
+  base::string16 word(UTF8ToUTF16("123startWithNumber"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("123"), iter.GetCurrentTerm());
@@ -72,7 +72,7 @@ TEST(TermBreakIteratorTest, StartsWithNumber) {
 
 TEST(TermBreakIteratorTest, CaseAndNoCase) {
   // "English" + two Chinese chars U+4E2D U+6587 + "Word"
-  string16 word(UTF8ToUTF16("English\xe4\xb8\xad\xe6\x96\x87Word"));
+  base::string16 word(UTF8ToUTF16("English\xe4\xb8\xad\xe6\x96\x87Word"));
   TermBreakIterator iter(word);
   EXPECT_TRUE(iter.Advance());
   EXPECT_EQ(UTF8ToUTF16("English"), iter.GetCurrentTerm());
diff --git a/chrome/browser/ui/app_list/search/tokenized_string.cc b/chrome/browser/ui/app_list/search/tokenized_string.cc
index 6769e2d..d2a0027 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string.cc
+++ b/chrome/browser/ui/app_list/search/tokenized_string.cc
@@ -13,7 +13,7 @@ using base::i18n::BreakIterator;
 
 namespace app_list {
 
-TokenizedString::TokenizedString(const string16& text)
+TokenizedString::TokenizedString(const base::string16& text)
     : text_(text) {
   Tokenize();
 }
@@ -28,7 +28,7 @@ void TokenizedString::Tokenize() {
     if (!break_iter.IsWord())
       continue;
 
-    const string16 word(break_iter.GetString());
+    const base::string16 word(break_iter.GetString());
     const size_t word_start = break_iter.prev();
     TermBreakIterator term_iter(word);
     while (term_iter.Advance()) {
diff --git a/chrome/browser/ui/app_list/search/tokenized_string.h b/chrome/browser/ui/app_list/search/tokenized_string.h
index 08ba723..94d4e53 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string.h
+++ b/chrome/browser/ui/app_list/search/tokenized_string.h
@@ -21,10 +21,10 @@ class TokenizedString {
   typedef std::vector<string16> Tokens;
   typedef std::vector<gfx::Range> Mappings;
 
-  explicit TokenizedString(const string16& text);
+  explicit TokenizedString(const base::string16& text);
   ~TokenizedString();
 
-  const string16& text() const { return text_; }
+  const base::string16& text() const { return text_; }
   const Tokens& tokens() const { return tokens_; }
   const Mappings& mappings() const { return mappings_; }
 
@@ -32,7 +32,7 @@ class TokenizedString {
   void Tokenize();
 
   // Input text.
-  const string16 text_;
+  const base::string16 text_;
 
   // Broken down tokens and the index mapping of tokens in original string.
   Tokens tokens_;
diff --git a/chrome/browser/ui/app_list/search/tokenized_string_match.cc b/chrome/browser/ui/app_list/search/tokenized_string_match.cc
index 5a68af6..8190b90 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string_match.cc
+++ b/chrome/browser/ui/app_list/search/tokenized_string_match.cc
@@ -95,8 +95,8 @@ bool TokenizedStringMatch::Calculate(const TokenizedString& query,
   return relevance_ > kNoMatchScore;
 }
 
-bool TokenizedStringMatch::Calculate(const string16& query,
-                                     const string16& text) {
+bool TokenizedStringMatch::Calculate(const base::string16& query,
+                                     const base::string16& text) {
   const TokenizedString tokenized_query(query);
   const TokenizedString tokenized_text(text);
   return Calculate(tokenized_query, tokenized_text);
diff --git a/chrome/browser/ui/app_list/search/tokenized_string_match.h b/chrome/browser/ui/app_list/search/tokenized_string_match.h
index 9f22392..99b84da 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string_match.h
+++ b/chrome/browser/ui/app_list/search/tokenized_string_match.h
@@ -33,7 +33,7 @@ class TokenizedStringMatch {
   bool Calculate(const TokenizedString& query, const TokenizedString& text);
 
   // Convenience wrapper to calculate match from raw string input.
-  bool Calculate(const string16& query, const string16& text);
+  bool Calculate(const base::string16& query, const base::string16& text);
 
   double relevance() const { return relevance_; }
   const Hits& hits() const { return hits_; }
diff --git a/chrome/browser/ui/app_list/search/tokenized_string_match_unittest.cc b/chrome/browser/ui/app_list/search/tokenized_string_match_unittest.cc
index af595bb..b167a29 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string_match_unittest.cc
+++ b/chrome/browser/ui/app_list/search/tokenized_string_match_unittest.cc
@@ -14,9 +14,9 @@ namespace test {
 
 // Returns a string of |text| marked the hits in |match| using block bracket.
 // e.g. text= "Text", hits = [{0,1}], returns "[T]ext".
-std::string MatchHit(const string16& text,
+std::string MatchHit(const base::string16& text,
                      const TokenizedStringMatch& match) {
-  string16 marked = text;
+  base::string16 marked = text;
 
   const TokenizedStringMatch::Hits& hits = match.hits();
   for (TokenizedStringMatch::Hits::const_reverse_iterator it = hits.rbegin();
@@ -44,7 +44,7 @@ TEST(TokenizedStringMatchTest, NotMatch) {
 
   TokenizedStringMatch match;
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kTestCases); ++i) {
-    const string16 text(UTF8ToUTF16(kTestCases[i].text));
+    const base::string16 text(UTF8ToUTF16(kTestCases[i].text));
     EXPECT_FALSE(match.Calculate(UTF8ToUTF16(kTestCases[i].query), text))
         << "Test case " << i
         << " : text=" << kTestCases[i].text
@@ -70,7 +70,7 @@ TEST(TokenizedStringMatchTest, Match) {
 
   TokenizedStringMatch match;
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kTestCases); ++i) {
-    const string16 text(UTF8ToUTF16(kTestCases[i].text));
+    const base::string16 text(UTF8ToUTF16(kTestCases[i].text));
     EXPECT_TRUE(match.Calculate(UTF8ToUTF16(kTestCases[i].query), text));
     EXPECT_EQ(kTestCases[i].expect, MatchHit(text, match));
   }
@@ -98,7 +98,7 @@ TEST(TokenizedStringMatchTest, Relevance) {
   TokenizedStringMatch match_low;
   TokenizedStringMatch match_high;
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kTestCases); ++i) {
-    const string16 text(UTF8ToUTF16(kTestCases[i].text));
+    const base::string16 text(UTF8ToUTF16(kTestCases[i].text));
     EXPECT_TRUE(
         match_low.Calculate(UTF8ToUTF16(kTestCases[i].query_low), text));
     EXPECT_TRUE(
diff --git a/chrome/browser/ui/app_list/search/tokenized_string_unittest.cc b/chrome/browser/ui/app_list/search/tokenized_string_unittest.cc
index dfccfce..4825834 100644
--- a/chrome/browser/ui/app_list/search/tokenized_string_unittest.cc
+++ b/chrome/browser/ui/app_list/search/tokenized_string_unittest.cc
@@ -16,7 +16,7 @@ string16 GetContent(const TokenizedString& tokenized) {
   const TokenizedString::Tokens& tokens = tokenized.tokens();
   const TokenizedString::Mappings& mappings = tokenized.mappings();
 
-  string16 str;
+  base::string16 str;
   for (size_t i = 0; i < tokens.size(); ++i) {
     if (i > 0)
       str += ' ';
@@ -29,56 +29,56 @@ string16 GetContent(const TokenizedString& tokenized) {
 }  // namespace
 
 TEST(TokenizedStringTest, Empty) {
-  string16 empty;
+  base::string16 empty;
   TokenizedString tokens(empty);
   EXPECT_EQ(string16(), GetContent(tokens));
 }
 
 TEST(TokenizedStringTest, Basic) {
   {
-    string16 text(UTF8ToUTF16("ScratchPad"));
+    base::string16 text(UTF8ToUTF16("ScratchPad"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("scratch{0,7} pad{7,10}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("Chess2.0"));
+    base::string16 text(UTF8ToUTF16("Chess2.0"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("chess{0,5} 2.0{5,8}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("Cut the rope"));
+    base::string16 text(UTF8ToUTF16("Cut the rope"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("cut{0,3} the{4,7} rope{8,12}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("AutoCAD WS"));
+    base::string16 text(UTF8ToUTF16("AutoCAD WS"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("auto{0,4} cad{4,7} ws{8,10}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("Great TweetDeck"));
+    base::string16 text(UTF8ToUTF16("Great TweetDeck"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("great{0,5} tweet{6,11} deck{11,15}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("Draw-It!"));
+    base::string16 text(UTF8ToUTF16("Draw-It!"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("draw{0,4} it{5,7}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("Faxing & Signing"));
+    base::string16 text(UTF8ToUTF16("Faxing & Signing"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16("faxing{0,6} signing{9,16}"),
               GetContent(tokens));
   }
   {
-    string16 text(UTF8ToUTF16("!@#$%^&*()<<<**>>>"));
+    base::string16 text(UTF8ToUTF16("!@#$%^&*()<<<**>>>"));
     TokenizedString tokens(text);
     EXPECT_EQ(UTF8ToUTF16(""),
               GetContent(tokens));
diff --git a/chrome/browser/ui/apps/app_metro_infobar_delegate_win.h b/chrome/browser/ui/apps/app_metro_infobar_delegate_win.h
index 03a384f..a38396e 100644
--- a/chrome/browser/ui/apps/app_metro_infobar_delegate_win.h
+++ b/chrome/browser/ui/apps/app_metro_infobar_delegate_win.h
@@ -34,11 +34,11 @@ class AppMetroInfoBarDelegateWin : public ConfirmInfoBarDelegate {
 
   // ConfirmInfoBarDelegate overrides:
   virtual int GetIconID() const OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
-  virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
   virtual bool Cancel() OVERRIDE;
-  virtual string16 GetLinkText() const OVERRIDE;
+  virtual base::string16 GetLinkText() const OVERRIDE;
   virtual bool LinkClicked(WindowOpenDisposition disposition) OVERRIDE;
 
   Mode mode_;
diff --git a/chrome/browser/ui/apps/directory_access_confirmation_dialog.cc b/chrome/browser/ui/apps/directory_access_confirmation_dialog.cc
index d8c51a5..905e734 100644
--- a/chrome/browser/ui/apps/directory_access_confirmation_dialog.cc
+++ b/chrome/browser/ui/apps/directory_access_confirmation_dialog.cc
@@ -16,15 +16,15 @@ namespace {
 class DirectoryAccessConfirmationDialog : public TabModalConfirmDialogDelegate {
  public:
   DirectoryAccessConfirmationDialog(bool writable,
-                                    const string16& app_name,
+                                    const base::string16& app_name,
                                     content::WebContents* web_contents,
                                     const base::Closure& on_accept,
                                     const base::Closure& on_cancel);
 
-  virtual string16 GetTitle() OVERRIDE;
-  virtual string16 GetMessage() OVERRIDE;
-  virtual string16 GetAcceptButtonTitle() OVERRIDE;
-  virtual string16 GetCancelButtonTitle() OVERRIDE;
+  virtual base::string16 GetTitle() OVERRIDE;
+  virtual base::string16 GetMessage() OVERRIDE;
+  virtual base::string16 GetAcceptButtonTitle() OVERRIDE;
+  virtual base::string16 GetCancelButtonTitle() OVERRIDE;
 
  private:
   virtual void OnAccepted() OVERRIDE;
@@ -34,12 +34,12 @@ class DirectoryAccessConfirmationDialog : public TabModalConfirmDialogDelegate {
   const base::Closure on_accept_;
   const base::Closure on_cancel_;
   const bool writable_;
-  const string16 app_name_;
+  const base::string16 app_name_;
 };
 
 DirectoryAccessConfirmationDialog::DirectoryAccessConfirmationDialog(
     bool writable,
-    const string16& app_name,
+    const base::string16& app_name,
     content::WebContents* web_contents,
     const base::Closure& on_accept,
     const base::Closure& on_cancel)
@@ -88,7 +88,7 @@ void DirectoryAccessConfirmationDialog::OnClosed() {
 }  // namespace
 
 void CreateDirectoryAccessConfirmationDialog(bool writable,
-                                             const string16& app_name,
+                                             const base::string16& app_name,
                                              content::WebContents* web_contents,
                                              const base::Closure& on_accept,
                                              const base::Closure& on_cancel) {
diff --git a/chrome/browser/ui/apps/directory_access_confirmation_dialog.h b/chrome/browser/ui/apps/directory_access_confirmation_dialog.h
index 7d7c2ec..c0a40b6 100644
--- a/chrome/browser/ui/apps/directory_access_confirmation_dialog.h
+++ b/chrome/browser/ui/apps/directory_access_confirmation_dialog.h
@@ -13,7 +13,7 @@ class WebContents;
 }
 
 void CreateDirectoryAccessConfirmationDialog(bool writable,
-                                             const string16& app_name,
+                                             const base::string16& app_name,
                                              content::WebContents* web_contents,
                                              const base::Closure& on_accept,
                                              const base::Closure& on_cancel);
diff --git a/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc b/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
index bbe4c89..b72fd14 100644
--- a/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
+++ b/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
@@ -111,10 +111,10 @@ void ChromeBrowserMainExtraPartsAura::DetectRunningAsRoot() {
     if (command_line.HasSwitch(switches::kUserDataDir))
       return;
 
-    string16 title = l10n_util::GetStringFUTF16(
+    base::string16 title = l10n_util::GetStringFUTF16(
         IDS_REFUSE_TO_RUN_AS_ROOT,
         l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
-    string16 message = l10n_util::GetStringFUTF16(
+    base::string16 message = l10n_util::GetStringFUTF16(
         IDS_REFUSE_TO_RUN_AS_ROOT_2,
         l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
 
diff --git a/chrome/browser/ui/bookmarks/bookmark_browsertest.cc b/chrome/browser/ui/bookmarks/bookmark_browsertest.cc
index 1ccb329..040be54 100644
--- a/chrome/browser/ui/bookmarks/bookmark_browsertest.cc
+++ b/chrome/browser/ui/bookmarks/bookmark_browsertest.cc
@@ -108,7 +108,8 @@ IN_PROC_BROWSER_TEST_F(BookmarkBrowsertest, DISABLED_MultiProfile) {
 
   ui_test_utils::BrowserAddedObserver observer;
   g_browser_process->profile_manager()->CreateMultiProfileAsync(
-      string16(), string16(), ProfileManager::CreateCallback(), std::string());
+      base::string16(), base::string16(), ProfileManager::CreateCallback(),
+      std::string());
   Browser* browser2 = observer.WaitForSingleNewBrowser();
   BookmarkModel* bookmark_model2 = WaitForBookmarkModel(browser2->profile());
 
diff --git a/chrome/browser/ui/bookmarks/bookmark_context_menu_controller.cc b/chrome/browser/ui/bookmarks/bookmark_context_menu_controller.cc
index e8e9caa..cb3b50f 100644
--- a/chrome/browser/ui/bookmarks/bookmark_context_menu_controller.cc
+++ b/chrome/browser/ui/bookmarks/bookmark_context_menu_controller.cc
@@ -213,7 +213,7 @@ void BookmarkContextMenuController::ExecuteCommand(int id, int event_flags) {
       const BookmarkNode* parent =
           bookmark_utils::GetParentForNewNodes(parent_, selection_, &index);
       GURL url;
-      string16 title;
+      base::string16 title;
       chrome::GetURLAndTitleToBookmark(
           browser_->tab_strip_model()->GetActiveWebContents(),
           &url, &title);
diff --git a/chrome/browser/ui/bookmarks/bookmark_editor.cc b/chrome/browser/ui/bookmarks/bookmark_editor.cc
index 7338c91..b8af440 100644
--- a/chrome/browser/ui/bookmarks/bookmark_editor.cc
+++ b/chrome/browser/ui/bookmarks/bookmark_editor.cc
@@ -99,7 +99,7 @@ BookmarkEditor::EditDetails BookmarkEditor::EditDetails::AddNodeInFolder(
     const BookmarkNode* parent_node,
     int index,
     const GURL& url,
-    const string16& title) {
+    const base::string16& title) {
   EditDetails details(NEW_URL);
   details.parent_node = parent_node;
   details.index = index;
diff --git a/chrome/browser/ui/bookmarks/bookmark_editor.h b/chrome/browser/ui/bookmarks/bookmark_editor.h
index 75f0f9b..782720d 100644
--- a/chrome/browser/ui/bookmarks/bookmark_editor.h
+++ b/chrome/browser/ui/bookmarks/bookmark_editor.h
@@ -45,7 +45,7 @@ class BookmarkEditor {
     static EditDetails AddNodeInFolder(const BookmarkNode* parent_node,
                                        int index,
                                        const GURL& url,
-                                       const string16& title);
+                                       const base::string16& title);
 
     // Returns an EditDetails instance for the user adding a folder within a
     // given parent node with a specified index.
@@ -85,11 +85,11 @@ class BookmarkEditor {
 
     // If type == NEW_URL this gives the URL/title.
     GURL url;
-    string16 title;
+    base::string16 title;
 
     // If type == NEW_FOLDER, this is the urls/title pairs to add to the
     // folder.
-    std::vector<std::pair<GURL, string16> > urls;
+    std::vector<std::pair<GURL, base::string16> > urls;
 
    private:
     explicit EditDetails(Type node_type);
diff --git a/chrome/browser/ui/bookmarks/bookmark_utils.cc b/chrome/browser/ui/bookmarks/bookmark_utils.cc
index f5b760b..4492aa2 100644
--- a/chrome/browser/ui/bookmarks/bookmark_utils.cc
+++ b/chrome/browser/ui/bookmarks/bookmark_utils.cc
@@ -131,9 +131,9 @@ int ChildURLCountTotal(const BookmarkNode* node) {
 
 // Returns in |urls|, the url and title pairs for each open tab in browser.
 void GetURLsForOpenTabs(Browser* browser,
-                        std::vector<std::pair<GURL, string16> >* urls) {
+                        std::vector<std::pair<GURL, base::string16> >* urls) {
   for (int i = 0; i < browser->tab_strip_model()->count(); ++i) {
-    std::pair<GURL, string16> entry;
+    std::pair<GURL, base::string16> entry;
     GetURLAndTitleToBookmark(browser->tab_strip_model()->GetWebContentsAt(i),
                              &(entry.first), &(entry.second));
     urls->push_back(entry);
@@ -244,7 +244,7 @@ GURL GetURLToBookmark(content::WebContents* web_contents) {
 
 void GetURLAndTitleToBookmark(content::WebContents* web_contents,
                               GURL* url,
-                              string16* title) {
+                              base::string16* title) {
   *url = GetURLToBookmark(web_contents);
   *title = web_contents->GetTitle();
 }
diff --git a/chrome/browser/ui/bookmarks/bookmark_utils.h b/chrome/browser/ui/bookmarks/bookmark_utils.h
index 8cd9abb..e9a6168 100644
--- a/chrome/browser/ui/bookmarks/bookmark_utils.h
+++ b/chrome/browser/ui/bookmarks/bookmark_utils.h
@@ -78,7 +78,7 @@ GURL GetURLToBookmark(content::WebContents* web_contents);
 // Fills in the URL and title for a bookmark of |web_contents|.
 void GetURLAndTitleToBookmark(content::WebContents* web_contents,
                               GURL* url,
-                              string16* title);
+                              base::string16* title);
 
 // Toggles whether the bookmark bar is shown only on the new tab page or on
 // all tabs. This is a preference modifier, not a visual modifier.
diff --git a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.cc b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.cc
index 88df062..4dc69e8 100644
--- a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.cc
+++ b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.cc
@@ -107,13 +107,13 @@ string16 RecentlyUsedFoldersComboModel::GetItemAt(int index) {
     case Item::TYPE_SEPARATOR:
       // This function should not be called for separators.
       NOTREACHED();
-      return string16();
+      return base::string16();
     case Item::TYPE_CHOOSE_ANOTHER_FOLDER:
       return l10n_util::GetStringUTF16(
           IDS_BOOKMARK_BUBBLE_CHOOSER_ANOTHER_FOLDER);
   }
   NOTREACHED();
-  return string16();
+  return base::string16();
 }
 
 bool RecentlyUsedFoldersComboModel::IsItemSeparatorAt(int index) {
diff --git a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.h b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.h
index a04f886..dab2808 100644
--- a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.h
+++ b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model.h
@@ -29,7 +29,7 @@ class RecentlyUsedFoldersComboModel
 
   // Overridden from ui::ComboboxModel:
   virtual int GetItemCount() const OVERRIDE;
-  virtual string16 GetItemAt(int index) OVERRIDE;
+  virtual base::string16 GetItemAt(int index) OVERRIDE;
   virtual bool IsItemSeparatorAt(int index) OVERRIDE;
   virtual int GetDefaultIndex() const OVERRIDE;
   virtual void AddObserver(ui::ComboboxModelObserver* observer) OVERRIDE;
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index 618de84..e69c802 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -122,7 +122,7 @@ const base::FilePath::CharType kDocRoot[] =
     FILE_PATH_LITERAL("chrome/test/data");
 
 // Given a page title, returns the expected window caption string.
-string16 WindowCaptionFromPageTitle(const string16& page_title) {
+string16 WindowCaptionFromPageTitle(const base::string16& page_title) {
 #if defined(OS_MACOSX) || defined(OS_CHROMEOS)
   // On Mac or ChromeOS, we don't want to suffix the page title with
   // the application name.
@@ -333,8 +333,9 @@ class BrowserTest : public ExtensionBrowserTest {
  protected:
   // In RTL locales wrap the page title with RTL embedding characters so that it
   // matches the value returned by GetWindowTitle().
-  string16 LocaleWindowCaptionFromPageTitle(const string16& expected_title) {
-    string16 page_title = WindowCaptionFromPageTitle(expected_title);
+  base::string16 LocaleWindowCaptionFromPageTitle(
+      const base::string16& expected_title) {
+    base::string16 page_title = WindowCaptionFromPageTitle(expected_title);
 #if defined(OS_WIN)
     std::string locale = g_browser_process->GetApplicationLocale();
     if (base::i18n::GetTextDirectionForLocale(locale.c_str()) ==
@@ -378,7 +379,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, NoTitle) {
                      base::FilePath(kTitle1File)));
   EXPECT_EQ(LocaleWindowCaptionFromPageTitle(ASCIIToUTF16("title1.html")),
             browser()->GetWindowTitleForCurrentTab());
-  string16 tab_title;
+  base::string16 tab_title;
   ASSERT_TRUE(ui_test_utils::GetCurrentTabTitle(browser(), &tab_title));
   EXPECT_EQ(ASCIIToUTF16("title1.html"), tab_title);
 }
@@ -396,10 +397,10 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, Title) {
       browser(), ui_test_utils::GetTestUrl(
                      base::FilePath(base::FilePath::kCurrentDirectory),
                      base::FilePath(kTitle2File)));
-  const string16 test_title(ASCIIToUTF16("Title Of Awesomeness"));
+  const base::string16 test_title(ASCIIToUTF16("Title Of Awesomeness"));
   EXPECT_EQ(LocaleWindowCaptionFromPageTitle(test_title),
             browser()->GetWindowTitleForCurrentTab());
-  string16 tab_title;
+  base::string16 tab_title;
   ASSERT_TRUE(ui_test_utils::GetCurrentTabTitle(browser(), &tab_title));
   EXPECT_EQ(test_title, tab_title);
 }
@@ -414,7 +415,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, JavascriptAlertActivatesTab) {
   WebContents* second_tab = browser()->tab_strip_model()->GetWebContentsAt(1);
   ASSERT_TRUE(second_tab);
   second_tab->GetRenderViewHost()->ExecuteJavascriptInWebFrame(
-      string16(),
+      base::string16(),
       ASCIIToUTF16("alert('Activate!');"));
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
   alert->CloseModalDialog();
@@ -477,7 +478,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, CrossProcessNavCancelsDialogs) {
   // See http://crbug.com/312490.
   WebContents* contents = browser()->tab_strip_model()->GetActiveWebContents();
   contents->GetRenderViewHost()->ExecuteJavascriptInWebFrame(
-      string16(),
+      base::string16(),
       ASCIIToUTF16("alert('one'); alert('two');"));
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
   EXPECT_TRUE(alert->IsValid());
@@ -1774,7 +1775,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, InterstitialClosesDialogs) {
 
   WebContents* contents = browser()->tab_strip_model()->GetActiveWebContents();
   contents->GetRenderViewHost()->ExecuteJavascriptInWebFrame(
-      string16(),
+      base::string16(),
       ASCIIToUTF16("alert('Dialog showing!');"));
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
   EXPECT_TRUE(alert->IsValid());
@@ -1979,7 +1980,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, WindowOpenClose) {
   GURL url = ui_test_utils::GetTestUrl(
       base::FilePath(), base::FilePath().AppendASCII("window.close.html"));
 
-  string16 title = ASCIIToUTF16("Title Of Awesomeness");
+  base::string16 title = ASCIIToUTF16("Title Of Awesomeness");
   content::TitleWatcher title_watcher(
       browser()->tab_strip_model()->GetActiveWebContents(), title);
   ui_test_utils::NavigateToURLBlockUntilNavigationsComplete(browser(), url, 2);
@@ -2029,7 +2030,7 @@ IN_PROC_BROWSER_TEST_F(ShowModalDialogTest, BasicTest) {
   GURL url = ui_test_utils::GetTestUrl(
       base::FilePath(), base::FilePath().AppendASCII("showmodaldialog.html"));
 
-  string16 expected_title(ASCIIToUTF16("SUCCESS"));
+  base::string16 expected_title(ASCIIToUTF16("SUCCESS"));
   content::TitleWatcher title_watcher(
       browser()->tab_strip_model()->GetActiveWebContents(), expected_title);
   ui_test_utils::NavigateToURL(browser(), url);
@@ -2043,7 +2044,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, DisallowFileUrlUniversalAccessTest) {
       base::FilePath(),
       base::FilePath().AppendASCII("fileurl_universalaccess.html"));
 
-  string16 expected_title(ASCIIToUTF16("Disallowed"));
+  base::string16 expected_title(ASCIIToUTF16("Disallowed"));
   content::TitleWatcher title_watcher(
       browser()->tab_strip_model()->GetActiveWebContents(), expected_title);
   title_watcher.AlsoWaitForTitle(ASCIIToUTF16("Allowed"));
@@ -2249,11 +2250,11 @@ class ClickModifierTest : public InProcessBrowserTest {
       base::FilePath(FILE_PATH_LITERAL("href.html")));
   }
 
-  string16 getFirstPageTitle() {
+  base::string16 getFirstPageTitle() {
     return ASCIIToUTF16(kFirstPageTitle);
   }
 
-  string16 getSecondPageTitle() {
+  base::string16 getSecondPageTitle() {
     return ASCIIToUTF16(kSecondPageTitle);
   }
 
diff --git a/chrome/browser/ui/browser_navigator_browsertest.cc b/chrome/browser/ui/browser_navigator_browsertest.cc
index 20c0723..87291e8 100644
--- a/chrome/browser/ui/browser_navigator_browsertest.cc
+++ b/chrome/browser/ui/browser_navigator_browsertest.cc
@@ -1331,9 +1331,9 @@ IN_PROC_BROWSER_TEST_F(BrowserNavigatorTest,
   ASSERT_TRUE(test_server()->Start());
 
   // Open a browser initiated POST request in new foreground tab.
-  string16 expected_title(base::ASCIIToUTF16(kExpectedTitle));
+  base::string16 expected_title(base::ASCIIToUTF16(kExpectedTitle));
   std::string post_data = kExpectedTitle;
-  string16 title;
+  base::string16 title;
   ASSERT_TRUE(OpenPOSTURLInNewForegroundTabAndGetTitle(
       test_server()->GetURL(kEchoTitleCommand), post_data, true, &title));
   EXPECT_EQ(expected_title, title);
@@ -1347,9 +1347,9 @@ IN_PROC_BROWSER_TEST_F(BrowserNavigatorTest,
   ASSERT_TRUE(test_server()->Start());
 
   // Open a renderer initiated POST request in new foreground tab.
-  string16 expected_title(base::ASCIIToUTF16(kExpectedTitle));
+  base::string16 expected_title(base::ASCIIToUTF16(kExpectedTitle));
   std::string post_data = kExpectedTitle;
-  string16 title;
+  base::string16 title;
   ASSERT_TRUE(OpenPOSTURLInNewForegroundTabAndGetTitle(
       test_server()->GetURL(kEchoTitleCommand), post_data, false, &title));
   EXPECT_NE(expected_title, title);
diff --git a/chrome/browser/ui/chrome_select_file_policy_unittest.cc b/chrome/browser/ui/chrome_select_file_policy_unittest.cc
index f57b874..1c739b5 100644
--- a/chrome/browser/ui/chrome_select_file_policy_unittest.cc
+++ b/chrome/browser/ui/chrome_select_file_policy_unittest.cc
@@ -47,7 +47,7 @@ class FileSelectionUser : public ui::SelectFileDialog::Listener {
         this, new ChromeSelectFilePolicy(NULL));
 
     const base::FilePath file_path;
-    const string16 title = string16();
+    const base::string16 title = base::string16();
 
     file_selection_initialisation_in_progress = true;
     select_file_dialog_->SelectFile(ui::SelectFileDialog::SELECT_OPEN_FILE,
diff --git a/chrome/browser/ui/confirm_bubble_model.cc b/chrome/browser/ui/confirm_bubble_model.cc
index 74d127b..9710910 100644
--- a/chrome/browser/ui/confirm_bubble_model.cc
+++ b/chrome/browser/ui/confirm_bubble_model.cc
@@ -29,7 +29,7 @@ void ConfirmBubbleModel::Cancel() {
 }
 
 string16 ConfirmBubbleModel::GetLinkText() const {
-  return string16();
+  return base::string16();
 }
 
 void ConfirmBubbleModel::LinkClicked() {
diff --git a/chrome/browser/ui/content_settings/content_setting_bubble_model.cc b/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
index 0cbb0dc..66671bc 100644
--- a/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
+++ b/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
@@ -243,7 +243,7 @@ bool ContentSettingSingleRadioGroup::settings_changed() const {
 // content type and setting the default value based on the content setting.
 void ContentSettingSingleRadioGroup::SetRadioGroup() {
   GURL url = web_contents()->GetURL();
-  string16 display_host;
+  base::string16 display_host;
   net::AppendFormattedHost(
       url,
       profile()->GetPrefs()->GetString(prefs::kAcceptLanguages),
@@ -655,7 +655,7 @@ void ContentSettingMediaStreamBubbleModel::SetRadioGroup() {
   RadioGroup radio_group;
   radio_group.url = url;
 
-  string16 display_host_utf16;
+  base::string16 display_host_utf16;
   net::AppendFormattedHost(
       url,
       profile()->GetPrefs()->GetString(prefs::kAcceptLanguages),
@@ -1015,7 +1015,7 @@ ContentSettingRPHBubbleModel::ContentSettingRPHBubbleModel(
   pending_handler_ = content_settings->pending_protocol_handler();
   previous_handler_ = content_settings->previous_protocol_handler();
 
-  string16 protocol;
+  base::string16 protocol;
   if (pending_handler_.protocol() == "mailto") {
     protocol = l10n_util::GetStringUTF16(
         IDS_REGISTER_PROTOCOL_HANDLER_MAILTO_NAME);
diff --git a/chrome/browser/ui/content_settings/media_setting_changed_infobar_delegate.h b/chrome/browser/ui/content_settings/media_setting_changed_infobar_delegate.h
index 7fdbe86..073c21f 100644
--- a/chrome/browser/ui/content_settings/media_setting_changed_infobar_delegate.h
+++ b/chrome/browser/ui/content_settings/media_setting_changed_infobar_delegate.h
@@ -24,9 +24,9 @@ class MediaSettingChangedInfoBarDelegate : public ConfirmInfoBarDelegate {
   // ConfirmInfoBarDelegate:
   virtual int GetIconID() const OVERRIDE;
   virtual Type GetInfoBarType() const OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
   virtual int GetButtons() const OVERRIDE;
-  virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
+  virtual base::string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSettingChangedInfoBarDelegate);
diff --git a/chrome/browser/ui/extensions/extension_install_ui_default.cc b/chrome/browser/ui/extensions/extension_install_ui_default.cc
index cec3a91..ba23037 100644
--- a/chrome/browser/ui/extensions/extension_install_ui_default.cc
+++ b/chrome/browser/ui/extensions/extension_install_ui_default.cc
@@ -91,9 +91,9 @@ class ErrorInfoBarDelegate : public ConfirmInfoBarDelegate {
   virtual ~ErrorInfoBarDelegate();
 
   // ConfirmInfoBarDelegate:
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
   virtual int GetButtons() const OVERRIDE;
-  virtual string16 GetLinkText() const OVERRIDE;
+  virtual base::string16 GetLinkText() const OVERRIDE;
   virtual bool LinkClicked(WindowOpenDisposition disposition) OVERRIDE;
 
   extensions::CrxInstallerError error_;
@@ -127,7 +127,7 @@ int ErrorInfoBarDelegate::GetButtons() const {
 
 string16 ErrorInfoBarDelegate::GetLinkText() const {
   return (error_.type() == extensions::CrxInstallerError::ERROR_OFF_STORE) ?
-      l10n_util::GetStringUTF16(IDS_LEARN_MORE) : string16();
+      l10n_util::GetStringUTF16(IDS_LEARN_MORE) : base::string16();
 }
 
 bool ErrorInfoBarDelegate::LinkClicked(WindowOpenDisposition disposition) {
diff --git a/chrome/browser/ui/find_bar/find_bar.h b/chrome/browser/ui/find_bar/find_bar.h
index 1be1b08..9fd85ef 100644
--- a/chrome/browser/ui/find_bar/find_bar.h
+++ b/chrome/browser/ui/find_bar/find_bar.h
@@ -58,11 +58,11 @@ class FindBar {
 
   // Set the text in the find box.
   virtual void SetFindTextAndSelectedRange(
-      const string16& find_text,
+      const base::string16& find_text,
       const gfx::Range& selected_range) = 0;
 
   // Gets the search string currently visible in the find box.
-  virtual string16 GetFindText() = 0;
+  virtual base::string16 GetFindText() = 0;
 
   // Gets the selection.
   virtual gfx::Range GetSelectedRange() = 0;
@@ -70,7 +70,7 @@ class FindBar {
   // Updates the FindBar with the find result details contained within the
   // specified |result|.
   virtual void UpdateUIForFindResult(const FindNotificationDetails& result,
-                                     const string16& find_text) = 0;
+                                     const base::string16& find_text) = 0;
 
   // No match was found; play an audible alert.
   virtual void AudibleAlert() = 0;
@@ -106,10 +106,10 @@ class FindBarTesting {
                                     bool* fully_visible) = 0;
 
   // Gets the search string currently selected in the Find box.
-  virtual string16 GetFindSelectedText() = 0;
+  virtual base::string16 GetFindSelectedText() = 0;
 
   // Gets the match count text (ie. 1 of 3) visible in the Find box.
-  virtual string16 GetMatchCountText() = 0;
+  virtual base::string16 GetMatchCountText() = 0;
 
   // Gets the pixel width of the FindBar.
   virtual int GetWidth() = 0;
diff --git a/chrome/browser/ui/find_bar/find_tab_helper.h b/chrome/browser/ui/find_bar/find_tab_helper.h
index 38fec42..1340851 100644
--- a/chrome/browser/ui/find_bar/find_tab_helper.h
+++ b/chrome/browser/ui/find_bar/find_tab_helper.h
@@ -53,10 +53,10 @@ class FindTabHelper : public content::WebContentsObserver,
 
   // Accessor for find_text_. Used to determine if this WebContents has any
   // active searches.
-  string16 find_text() const { return find_text_; }
+  base::string16 find_text() const { return find_text_; }
 
   // Accessor for the previous search we issued.
-  string16 previous_find_text() const { return previous_find_text_; }
+  base::string16 previous_find_text() const { return previous_find_text_; }
 
   gfx::Range selected_range() const { return selected_range_; }
   void set_selected_range(const gfx::Range& selected_range) {
@@ -109,10 +109,10 @@ class FindTabHelper : public content::WebContentsObserver,
   // The current string we are/just finished searching for. This is used to
   // figure out if this is a Find or a FindNext operation (FindNext should not
   // increase the request id).
-  string16 find_text_;
+  base::string16 find_text_;
 
   // The string we searched for before |find_text_|.
-  string16 previous_find_text_;
+  base::string16 previous_find_text_;
 
   // The selection within the text.
   gfx::Range selected_range_;
diff --git a/chrome/browser/ui/fullscreen/fullscreen_exit_bubble.h b/chrome/browser/ui/fullscreen/fullscreen_exit_bubble.h
index ed8671a..630c92a 100644
--- a/chrome/browser/ui/fullscreen/fullscreen_exit_bubble.h
+++ b/chrome/browser/ui/fullscreen/fullscreen_exit_bubble.h
@@ -75,12 +75,12 @@ class FullscreenExitBubble : public gfx::AnimationDelegate {
   void Cancel();
 
   // The following strings may change according to the content type and URL.
-  string16 GetCurrentMessageText() const;
-  string16 GetCurrentDenyButtonText() const;
+  base::string16 GetCurrentMessageText() const;
+  base::string16 GetCurrentDenyButtonText() const;
 
   // The following strings never change.
-  string16 GetAllowButtonText() const;
-  string16 GetInstructionText() const;
+  base::string16 GetAllowButtonText() const;
+  base::string16 GetInstructionText() const;
 
   // The browser this bubble is in.
   Browser* browser_;
diff --git a/chrome/browser/ui/fullscreen/fullscreen_exit_bubble_type.cc b/chrome/browser/ui/fullscreen/fullscreen_exit_bubble_type.cc
index 0a107bd..6f954c41 100644
--- a/chrome/browser/ui/fullscreen/fullscreen_exit_bubble_type.cc
+++ b/chrome/browser/ui/fullscreen/fullscreen_exit_bubble_type.cc
@@ -18,7 +18,7 @@ namespace fullscreen_bubble {
 string16 GetLabelTextForType(FullscreenExitBubbleType type,
                              const GURL& url,
                              ExtensionService* extension_service) {
-  string16 host(UTF8ToUTF16(url.host()));
+  base::string16 host(UTF8ToUTF16(url.host()));
   if (extension_service) {
     const ExtensionSet* extensions = extension_service->extensions();
     DCHECK(extensions);
@@ -56,7 +56,7 @@ string16 GetLabelTextForType(FullscreenExitBubbleType type,
             IDS_FULLSCREEN_UNKNOWN_EXTENSION_TRIGGERED_FULLSCREEN);
       default:
         NOTREACHED();
-        return string16();
+        return base::string16();
     }
   }
   switch (type) {
@@ -86,7 +86,7 @@ string16 GetLabelTextForType(FullscreenExitBubbleType type,
           IDS_FULLSCREEN_EXTENSION_TRIGGERED_FULLSCREEN, host);
     default:
       NOTREACHED();
-      return string16();
+      return base::string16();
   }
 }
 
@@ -104,10 +104,10 @@ string16 GetDenyButtonTextForType(FullscreenExitBubbleType type) {
     case FEB_TYPE_BROWSER_FULLSCREEN_EXIT_INSTRUCTION:
     case FEB_TYPE_BROWSER_EXTENSION_FULLSCREEN_EXIT_INSTRUCTION:
       NOTREACHED();  // No button in this case.
-      return string16();
+      return base::string16();
     default:
       NOTREACHED();
-      return string16();
+      return base::string16();
   }
 }
 
diff --git a/chrome/browser/ui/global_error/global_error.h b/chrome/browser/ui/global_error/global_error.h
index cacd1ff..23d0175 100644
--- a/chrome/browser/ui/global_error/global_error.h
+++ b/chrome/browser/ui/global_error/global_error.h
@@ -40,7 +40,7 @@ class GlobalError {
   // Returns the command ID for the menu item.
   virtual int MenuItemCommandID() = 0;
   // Returns the label for the menu item.
-  virtual string16 MenuItemLabel() = 0;
+  virtual base::string16 MenuItemLabel() = 0;
   // Returns the resource ID for the menu item icon.
   int MenuItemIconResourceID();
   // Called when the user clicks on the menu item.
@@ -69,16 +69,16 @@ class GlobalErrorWithStandardBubble
   // Returns an icon to use for the bubble view.
   virtual gfx::Image GetBubbleViewIcon();
   // Returns the title for the bubble view.
-  virtual string16 GetBubbleViewTitle() = 0;
+  virtual base::string16 GetBubbleViewTitle() = 0;
   // Returns the messages for the bubble view, one per line. Multiple messages
   // are only supported on Views.
   // TODO(yoz): Add multi-line support for GTK and Cocoa.
   virtual std::vector<string16> GetBubbleViewMessages() = 0;
   // Returns the accept button label for the bubble view.
-  virtual string16 GetBubbleViewAcceptButtonLabel() = 0;
+  virtual base::string16 GetBubbleViewAcceptButtonLabel() = 0;
   // Returns the cancel button label for the bubble view. To hide the cancel
   // button return an empty string.
-  virtual string16 GetBubbleViewCancelButtonLabel() = 0;
+  virtual base::string16 GetBubbleViewCancelButtonLabel() = 0;
   // Called when the bubble view is closed. |browser| is the Browser that the
   // bubble view was shown on.
   void BubbleViewDidClose(Browser* browser);
diff --git a/chrome/browser/ui/global_error/global_error_service_browsertest.cc b/chrome/browser/ui/global_error/global_error_service_browsertest.cc
index 2da6440..cb731e5 100644
--- a/chrome/browser/ui/global_error/global_error_service_browsertest.cc
+++ b/chrome/browser/ui/global_error/global_error_service_browsertest.cc
@@ -26,24 +26,24 @@ class BubbleViewError : public GlobalErrorWithStandardBubble {
     ADD_FAILURE();
     return 0;
   }
-  virtual string16 MenuItemLabel() OVERRIDE {
+  virtual base::string16 MenuItemLabel() OVERRIDE {
     ADD_FAILURE();
-    return string16();
+    return base::string16();
   }
   virtual void ExecuteMenuItem(Browser* browser) OVERRIDE { ADD_FAILURE(); }
 
   virtual bool HasBubbleView() OVERRIDE { return true; }
-  virtual string16 GetBubbleViewTitle() OVERRIDE {
-    return string16();
+  virtual base::string16 GetBubbleViewTitle() OVERRIDE {
+    return base::string16();
   }
   virtual std::vector<string16> GetBubbleViewMessages() OVERRIDE {
     return std::vector<string16>();
   }
-  virtual string16 GetBubbleViewAcceptButtonLabel() OVERRIDE {
-    return string16();
+  virtual base::string16 GetBubbleViewAcceptButtonLabel() OVERRIDE {
+    return base::string16();
   }
-  virtual string16 GetBubbleViewCancelButtonLabel() OVERRIDE {
-    return string16();
+  virtual base::string16 GetBubbleViewCancelButtonLabel() OVERRIDE {
+    return base::string16();
   }
   virtual void OnBubbleViewDidClose(Browser* browser) OVERRIDE {
     EXPECT_TRUE(browser);
diff --git a/chrome/browser/ui/global_error/global_error_service_unittest.cc b/chrome/browser/ui/global_error/global_error_service_unittest.cc
index 9010229..5493392 100644
--- a/chrome/browser/ui/global_error/global_error_service_unittest.cc
+++ b/chrome/browser/ui/global_error/global_error_service_unittest.cc
@@ -24,9 +24,9 @@ class BaseError : public GlobalError {
     ADD_FAILURE();
     return 0;
   }
-  virtual string16 MenuItemLabel() OVERRIDE {
+  virtual base::string16 MenuItemLabel() OVERRIDE {
     ADD_FAILURE();
-    return string16();
+    return base::string16();
   }
   virtual void ExecuteMenuItem(Browser* browser) OVERRIDE { ADD_FAILURE(); }
 
@@ -56,7 +56,7 @@ class MenuError : public BaseError {
 
   virtual bool HasMenuItem() OVERRIDE { return true; }
   virtual int MenuItemCommandID() OVERRIDE { return command_id_; }
-  virtual string16 MenuItemLabel() OVERRIDE { return string16(); }
+  virtual base::string16 MenuItemLabel() OVERRIDE { return base::string16(); }
   virtual void ExecuteMenuItem(Browser* browser) OVERRIDE {}
 
  private:
diff --git a/chrome/browser/ui/hung_plugin_tab_helper.cc b/chrome/browser/ui/hung_plugin_tab_helper.cc
index c4da8bd..6ed3507 100644
--- a/chrome/browser/ui/hung_plugin_tab_helper.cc
+++ b/chrome/browser/ui/hung_plugin_tab_helper.cc
@@ -135,33 +135,33 @@ class HungPluginInfoBarDelegate : public ConfirmInfoBarDelegate {
   static InfoBar* Create(InfoBarService* infobar_service,
                          HungPluginTabHelper* helper,
                          int plugin_child_id,
-                         const string16& plugin_name);
+                         const base::string16& plugin_name);
 
  private:
   HungPluginInfoBarDelegate(HungPluginTabHelper* helper,
                             int plugin_child_id,
-                            const string16& plugin_name);
+                            const base::string16& plugin_name);
   virtual ~HungPluginInfoBarDelegate();
 
   // ConfirmInfoBarDelegate:
   virtual int GetIconID() const OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
   virtual int GetButtons() const OVERRIDE;
-  virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
+  virtual base::string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
 
   HungPluginTabHelper* helper_;
   int plugin_child_id_;
 
-  string16 message_;
-  string16 button_text_;
+  base::string16 message_;
+  base::string16 button_text_;
 };
 
 // static
 InfoBar* HungPluginInfoBarDelegate::Create(InfoBarService* infobar_service,
                                            HungPluginTabHelper* helper,
                                            int plugin_child_id,
-                                           const string16& plugin_name) {
+                                           const base::string16& plugin_name) {
   return infobar_service->AddInfoBar(ConfirmInfoBarDelegate::CreateInfoBar(
       scoped_ptr<ConfirmInfoBarDelegate>(new HungPluginInfoBarDelegate(
           helper, plugin_child_id, plugin_name))));
@@ -170,7 +170,7 @@ InfoBar* HungPluginInfoBarDelegate::Create(InfoBarService* infobar_service,
 HungPluginInfoBarDelegate::HungPluginInfoBarDelegate(
     HungPluginTabHelper* helper,
     int plugin_child_id,
-    const string16& plugin_name)
+    const base::string16& plugin_name)
     : ConfirmInfoBarDelegate(),
       helper_(helper),
       plugin_child_id_(plugin_child_id),
@@ -213,11 +213,11 @@ bool HungPluginInfoBarDelegate::Accept() {
 // not we're currently showing the infobar.
 struct HungPluginTabHelper::PluginState {
   // Initializes the plugin state to be a hung plugin.
-  PluginState(const base::FilePath& p, const string16& n);
+  PluginState(const base::FilePath& p, const base::string16& n);
   ~PluginState();
 
   base::FilePath path;
-  string16 name;
+  base::string16 name;
 
   // Possibly-null if we're not showing an infobar right now.
   InfoBar* infobar;
@@ -242,7 +242,7 @@ struct HungPluginTabHelper::PluginState {
 const int HungPluginTabHelper::PluginState::kInitialReshowDelaySec = 10;
 
 HungPluginTabHelper::PluginState::PluginState(const base::FilePath& p,
-                                              const string16& n)
+                                              const base::string16& n)
     : path(p),
       name(n),
       infobar(NULL),
@@ -310,7 +310,7 @@ void HungPluginTabHelper::PluginHungStatusChanged(
     return;
   }
 
-  string16 plugin_name =
+  base::string16 plugin_name =
       content::PluginService::GetInstance()->GetPluginDisplayNameByPath(
           plugin_path);
 
diff --git a/chrome/browser/ui/metro_pin_tab_helper_win.cc b/chrome/browser/ui/metro_pin_tab_helper_win.cc
index 7ae61c3..9f1dc00 100644
--- a/chrome/browser/ui/metro_pin_tab_helper_win.cc
+++ b/chrome/browser/ui/metro_pin_tab_helper_win.cc
@@ -43,7 +43,7 @@ const char kMetroPinMetric[] = "Metro.SecondaryTilePin";
 
 // Generate an ID for the tile based on |url_str|. The ID is simply a hash of
 // the URL.
-string16 GenerateTileId(const string16& url_str) {
+string16 GenerateTileId(const base::string16& url_str) {
   uint8 hash[crypto::kSHA256Length];
   crypto::SHA256HashString(UTF16ToUTF8(url_str), hash, sizeof(hash));
   std::string hash_str = base::HexEncode(hash, sizeof(hash));
@@ -68,7 +68,7 @@ base::FilePath GetTileImagesDir() {
 // |logo_dir|. The path of any created logo is returned in |logo_path|. Return
 // value indicates whether a site specific logo was created.
 bool CreateSiteSpecificLogo(const SkBitmap& bitmap,
-                            const string16& tile_id,
+                            const base::string16& tile_id,
                             const base::FilePath& logo_dir,
                             base::FilePath* logo_path) {
   const int kLogoWidth = 120;
@@ -152,8 +152,8 @@ class PinPageTaskRunner : public base::RefCountedThreadSafe<PinPageTaskRunner> {
   // Creates a task runner for the pinning operation with the given details.
   // |favicon| can be a null image (i.e. favicon.isNull() can be true), in
   // which case the backup tile image will be used.
-  PinPageTaskRunner(const string16& title,
-                    const string16& url,
+  PinPageTaskRunner(const base::string16& title,
+                    const base::string16& url,
                     const SkBitmap& favicon);
 
   void Run();
@@ -163,16 +163,16 @@ class PinPageTaskRunner : public base::RefCountedThreadSafe<PinPageTaskRunner> {
   ~PinPageTaskRunner() {}
 
   // Details of the page being pinned.
-  const string16 title_;
-  const string16 url_;
+  const base::string16 title_;
+  const base::string16 url_;
   SkBitmap favicon_;
 
   friend class base::RefCountedThreadSafe<PinPageTaskRunner>;
   DISALLOW_COPY_AND_ASSIGN(PinPageTaskRunner);
 };
 
-PinPageTaskRunner::PinPageTaskRunner(const string16& title,
-                                     const string16& url,
+PinPageTaskRunner::PinPageTaskRunner(const base::string16& title,
+                                     const base::string16& url,
                                      const SkBitmap& favicon)
     : title_(title),
       url_(url),
@@ -190,7 +190,7 @@ void PinPageTaskRunner::Run() {
 void PinPageTaskRunner::RunOnFileThread() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
 
-  string16 tile_id = GenerateTileId(url_);
+  base::string16 tile_id = GenerateTileId(url_);
   base::FilePath logo_dir = GetTileImagesDir();
   if (logo_dir.empty()) {
     LOG(ERROR) << "Could not create directory to store tile image.";
@@ -232,8 +232,8 @@ void PinPageTaskRunner::RunOnFileThread() {
 class MetroPinTabHelper::FaviconChooser {
  public:
   FaviconChooser(MetroPinTabHelper* helper,
-                 const string16& title,
-                 const string16& url,
+                 const base::string16& title,
+                 const base::string16& url,
                  const SkBitmap& history_bitmap);
 
   ~FaviconChooser() {}
@@ -254,8 +254,8 @@ class MetroPinTabHelper::FaviconChooser {
   MetroPinTabHelper* helper_;
 
   // Title and URL of the page being pinned.
-  const string16 title_;
-  const string16 url_;
+  const base::string16 title_;
+  const base::string16 url_;
 
   // The best candidate we have so far for the current pin operation.
   SkBitmap best_candidate_;
@@ -268,8 +268,8 @@ class MetroPinTabHelper::FaviconChooser {
 
 MetroPinTabHelper::FaviconChooser::FaviconChooser(
     MetroPinTabHelper* helper,
-    const string16& title,
-    const string16& url,
+    const base::string16& title,
+    const base::string16& url,
     const SkBitmap& history_bitmap)
         : helper_(helper),
           title_(title),
@@ -345,7 +345,7 @@ bool MetroPinTabHelper::IsPinned() const {
   if (!metro_module)
     return false;
 
-  typedef BOOL (*MetroIsPinnedToStartScreen)(const string16&);
+  typedef BOOL (*MetroIsPinnedToStartScreen)(const base::string16&);
   MetroIsPinnedToStartScreen metro_is_pinned_to_start_screen =
       reinterpret_cast<MetroIsPinnedToStartScreen>(
           ::GetProcAddress(metro_module, "MetroIsPinnedToStartScreen"));
@@ -355,7 +355,7 @@ bool MetroPinTabHelper::IsPinned() const {
   }
 
   GURL url = web_contents()->GetURL();
-  string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
+  base::string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
   return metro_is_pinned_to_start_screen(tile_id) != 0;
 }
 
@@ -372,8 +372,8 @@ void MetroPinTabHelper::TogglePinnedToStartScreen() {
                             base::win::METRO_PIN_INITIATED,
                             base::win::METRO_PIN_STATE_LIMIT);
   GURL url = web_contents()->GetURL();
-  string16 url_str = UTF8ToUTF16(url.spec());
-  string16 title = web_contents()->GetTitle();
+  base::string16 url_str = UTF8ToUTF16(url.spec());
+  base::string16 title = web_contents()->GetTitle();
   // TODO(oshima): Use scoped_ptr::Pass to pass it to other thread.
   SkBitmap favicon;
   FaviconTabHelper* favicon_tab_helper = FaviconTabHelper::FromWebContents(
@@ -449,7 +449,7 @@ void MetroPinTabHelper::UnPinPageFromStartScreen() {
   }
 
   GURL url = web_contents()->GetURL();
-  string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
+  base::string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
   metro_un_pin_from_start_screen(tile_id,
                                  base::Bind(&PinPageReportUmaCallback));
 }
diff --git a/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.cc b/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.cc
index d1b5bc4..1c82f43 100644
--- a/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.cc
+++ b/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.cc
@@ -24,7 +24,7 @@ AlternateNavInfoBarDelegate::~AlternateNavInfoBarDelegate() {
 // static
 void AlternateNavInfoBarDelegate::Create(
     content::WebContents* web_contents,
-    const string16& text,
+    const base::string16& text,
     const AutocompleteMatch& match,
     const GURL& search_url) {
   InfoBarService* infobar_service =
@@ -37,7 +37,7 @@ void AlternateNavInfoBarDelegate::Create(
 
 AlternateNavInfoBarDelegate::AlternateNavInfoBarDelegate(
     Profile* profile,
-    const string16& text,
+    const base::string16& text,
     const AutocompleteMatch& match,
     const GURL& search_url)
     : InfoBarDelegate(),
@@ -54,8 +54,8 @@ AlternateNavInfoBarDelegate::AlternateNavInfoBarDelegate(
 
 string16 AlternateNavInfoBarDelegate::GetMessageTextWithOffset(
     size_t* link_offset) const {
-  const string16 label = l10n_util::GetStringFUTF16(
-      IDS_ALTERNATE_NAV_URL_VIEW_LABEL, string16(), link_offset);
+  const base::string16 label = l10n_util::GetStringFUTF16(
+      IDS_ALTERNATE_NAV_URL_VIEW_LABEL, base::string16(), link_offset);
   return label;
 }
 
diff --git a/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.h b/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.h
index 7c92901..e27b864 100644
--- a/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.h
+++ b/chrome/browser/ui/omnibox/alternate_nav_infobar_delegate.h
@@ -16,17 +16,17 @@ class AlternateNavInfoBarDelegate : public InfoBarDelegate {
   // Creates an alternate nav infobar and delegate and adds the infobar to the
   // infobar service for |web_contents|.
   static void Create(content::WebContents* web_contents,
-                     const string16& text,
+                     const base::string16& text,
                      const AutocompleteMatch& match,
                      const GURL& search_url);
 
-  string16 GetMessageTextWithOffset(size_t* link_offset) const;
-  string16 GetLinkText() const;
+  base::string16 GetMessageTextWithOffset(size_t* link_offset) const;
+  base::string16 GetLinkText() const;
   bool LinkClicked(WindowOpenDisposition disposition);
 
  private:
   AlternateNavInfoBarDelegate(Profile* profile,
-                              const string16& text,
+                              const base::string16& text,
                               const AutocompleteMatch& match,
                               const GURL& search_url);
 
@@ -39,7 +39,7 @@ class AlternateNavInfoBarDelegate : public InfoBarDelegate {
   virtual Type GetInfoBarType() const OVERRIDE;
 
   Profile* profile_;
-  const string16 text_;
+  const base::string16 text_;
   const AutocompleteMatch match_;
   const GURL search_url_;
 
diff --git a/chrome/browser/ui/omnibox/location_bar_util.cc b/chrome/browser/ui/omnibox/location_bar_util.cc
index 8bfffbd..3c327a0 100644
--- a/chrome/browser/ui/omnibox/location_bar_util.cc
+++ b/chrome/browser/ui/omnibox/location_bar_util.cc
@@ -16,13 +16,13 @@
 
 namespace location_bar_util {
 
-string16 CalculateMinString(const string16& description) {
+string16 CalculateMinString(const base::string16& description) {
   // Chop at the first '.' or whitespace.
   const size_t dot_index = description.find('.');
   const size_t ws_index = description.find_first_of(base::kWhitespaceUTF16);
   size_t chop_index = std::min(dot_index, ws_index);
-  string16 min_string;
-  if (chop_index == string16::npos) {
+  base::string16 min_string;
+  if (chop_index == base::string16::npos) {
     // No dot or whitespace, truncate to at most 3 chars.
     min_string = gfx::TruncateString(description, 3);
   } else {
diff --git a/chrome/browser/ui/omnibox/location_bar_util.h b/chrome/browser/ui/omnibox/location_bar_util.h
index e9eb7e9..0f9e8a8 100644
--- a/chrome/browser/ui/omnibox/location_bar_util.h
+++ b/chrome/browser/ui/omnibox/location_bar_util.h
@@ -18,7 +18,7 @@ class Rect;
 namespace location_bar_util {
 
 // Build a short string to use in keyword-search when the field isn't very big.
-string16 CalculateMinString(const string16& description);
+string16 CalculateMinString(const base::string16& description);
 
 // Paint the background and border for |action| on |tab_id|.  |bounds| should
 // include the top and bottom of the location bar, and the middle column
diff --git a/chrome/browser/ui/omnibox/omnibox_controller.cc b/chrome/browser/ui/omnibox/omnibox_controller.cc
index 087a1fd..903f314 100644
--- a/chrome/browser/ui/omnibox/omnibox_controller.cc
+++ b/chrome/browser/ui/omnibox/omnibox_controller.cc
@@ -65,7 +65,7 @@ OmniboxController::~OmniboxController() {
 }
 
 void OmniboxController::StartAutocomplete(
-    string16 user_text,
+    base::string16 user_text,
     size_t cursor_position,
     const GURL& current_url,
     AutocompleteInput::PageClassification current_page_classification,
@@ -78,7 +78,7 @@ void OmniboxController::StartAutocomplete(
   // We don't explicitly clear OmniboxPopupModel::manually_selected_match, as
   // Start ends up invoking OmniboxPopupModel::OnResultChanged which clears it.
   autocomplete_controller_->Start(AutocompleteInput(
-      user_text, cursor_position, string16(), current_url,
+      user_text, cursor_position, base::string16(), current_url,
       current_page_classification, prevent_inline_autocomplete,
       prefer_keyword, allow_exact_keyword_match,
       AutocompleteInput::ALL_MATCHES));
@@ -115,8 +115,8 @@ void OmniboxController::OnResultChanged(bool default_match_changed) {
     } else {
       InvalidateCurrentMatch();
       popup_->OnResultChanged();
-      omnibox_edit_model_->OnPopupDataChanged(string16(), NULL, string16(),
-                                              false);
+      omnibox_edit_model_->OnPopupDataChanged(base::string16(), NULL,
+                                              base::string16(), false);
     }
   } else {
     popup_->OnResultChanged();
diff --git a/chrome/browser/ui/omnibox/omnibox_controller.h b/chrome/browser/ui/omnibox/omnibox_controller.h
index e5e2d97..326f1f9 100644
--- a/chrome/browser/ui/omnibox/omnibox_controller.h
+++ b/chrome/browser/ui/omnibox/omnibox_controller.h
@@ -42,7 +42,7 @@ class OmniboxController : public AutocompleteControllerDelegate {
 
   // |current_url| is only set for mobile ports.
   void StartAutocomplete(
-      string16 user_text,
+      base::string16 user_text,
       size_t cursor_position,
       const GURL& current_url,
       AutocompleteInput::PageClassification current_page_classification,
diff --git a/chrome/browser/ui/omnibox/omnibox_edit_model.cc b/chrome/browser/ui/omnibox/omnibox_edit_model.cc
index 20f6e72..9ce8881 100644
--- a/chrome/browser/ui/omnibox/omnibox_edit_model.cc
+++ b/chrome/browser/ui/omnibox/omnibox_edit_model.cc
@@ -105,8 +105,8 @@ const char kFocusToEditTimeHistogram[] = "Omnibox.FocusToEditTime";
 // between focusing and opening an omnibox match.
 const char kFocusToOpenTimeHistogram[] = "Omnibox.FocusToOpenTime";
 
-void RecordPercentageMatchHistogram(const string16& old_text,
-                                    const string16& new_text,
+void RecordPercentageMatchHistogram(const base::string16& old_text,
+                                    const base::string16& new_text,
                                     bool url_replacement_active,
                                     content::PageTransition transition) {
   size_t avg_length = (old_text.length() + new_text.length()) / 2;
@@ -114,8 +114,8 @@ void RecordPercentageMatchHistogram(const string16& old_text,
   int percent = 0;
   if (!old_text.empty() && !new_text.empty()) {
     size_t shorter_length = std::min(old_text.length(), new_text.length());
-    string16::const_iterator end(old_text.begin() + shorter_length);
-    string16::const_iterator mismatch(
+    base::string16::const_iterator end(old_text.begin() + shorter_length);
+    base::string16::const_iterator mismatch(
         std::mismatch(old_text.begin(), end, new_text.begin()).first);
     size_t matching_characters = mismatch - old_text.begin();
     percent = static_cast<float>(matching_characters) / avg_length * 100;
@@ -146,9 +146,9 @@ void RecordPercentageMatchHistogram(const string16& old_text,
 // OmniboxEditModel::State ----------------------------------------------------
 
 OmniboxEditModel::State::State(bool user_input_in_progress,
-                               const string16& user_text,
-                               const string16& gray_text,
-                               const string16& keyword,
+                               const base::string16& user_text,
+                               const base::string16& gray_text,
+                               const base::string16& keyword,
                                bool is_keyword_hint,
                                bool url_replacement_enabled,
                                OmniboxFocusState focus_state,
@@ -201,7 +201,7 @@ const OmniboxEditModel::State OmniboxEditModel::GetStateForTabSwitch() {
     // Weird edge case to match other browsers: if the edit is empty, revert to
     // the permanent text (so the user can get it back easily) but select it (so
     // on switching back, typing will "just work").
-    const string16 user_text(UserTextFromDisplayText(view_->GetText()));
+    const base::string16 user_text(UserTextFromDisplayText(view_->GetText()));
     if (user_text.empty()) {
       base::AutoReset<bool> tmp(&in_revert_, true);
       view_->RevertAll();
@@ -283,8 +283,8 @@ bool OmniboxEditModel::UpdatePermanentText() {
   // process -- before and after the auto-commit, the omnibox should show the
   // same user text and the same instant suggestion, even if the auto-commit
   // happens while the edit doesn't have focus.
-  string16 new_permanent_text = controller_->GetToolbarModel()->GetText();
-  string16 gray_text = view_->GetGrayTextAutocompletion();
+  base::string16 new_permanent_text = controller_->GetToolbarModel()->GetText();
+  base::string16 gray_text = view_->GetGrayTextAutocompletion();
   const bool visibly_changed_permanent_text =
       (permanent_text_ != new_permanent_text) &&
       (!has_focus() ||
@@ -302,7 +302,7 @@ GURL OmniboxEditModel::PermanentURL() {
   return URLFixerUpper::FixupURL(UTF16ToUTF8(permanent_text_), std::string());
 }
 
-void OmniboxEditModel::SetUserText(const string16& text) {
+void OmniboxEditModel::SetUserText(const base::string16& text) {
   SetInputInProgress(true);
   InternalSetUserText(text);
   omnibox_controller_->InvalidateCurrentMatch();
@@ -311,11 +311,11 @@ void OmniboxEditModel::SetUserText(const string16& text) {
 }
 
 bool OmniboxEditModel::CommitSuggestedText() {
-  const string16 suggestion = view_->GetGrayTextAutocompletion();
+  const base::string16 suggestion = view_->GetGrayTextAutocompletion();
   if (suggestion.empty())
     return false;
 
-  const string16 final_text = view_->GetText() + suggestion;
+  const base::string16 final_text = view_->GetText() + suggestion;
   view_->OnBeforePossibleChange();
   view_->SetWindowTextAndCaretPos(final_text, final_text.length(), false,
       false);
@@ -377,7 +377,7 @@ void OmniboxEditModel::OnChanged() {
 }
 
 void OmniboxEditModel::GetDataForURLExport(GURL* url,
-                                           string16* title,
+                                           base::string16* title,
                                            gfx::Image* favicon) {
   *url = CurrentMatch(NULL).destination_url;
   if (*url == URLFixerUpper::FixupURL(UTF16ToUTF8(permanent_text_),
@@ -409,7 +409,7 @@ AutocompleteMatch::Type OmniboxEditModel::CurrentTextType() const {
 
 void OmniboxEditModel::AdjustTextForCopy(int sel_min,
                                          bool is_all_selected,
-                                         string16* text,
+                                         base::string16* text,
                                          GURL* url,
                                          bool* write_url) {
   *write_url = false;
@@ -447,7 +447,7 @@ void OmniboxEditModel::AdjustTextForCopy(int sel_min,
   if (perm_url.SchemeIs(content::kHttpScheme) &&
       url->SchemeIs(content::kHttpScheme) && perm_url.host() == url->host()) {
     *write_url = true;
-    string16 http = ASCIIToUTF16(content::kHttpScheme) +
+    base::string16 http = ASCIIToUTF16(content::kHttpScheme) +
         ASCIIToUTF16(content::kStandardSchemeSeparator);
     if (text->compare(0, http.length(), http) != 0)
       *text = http + *text;
@@ -485,7 +485,7 @@ void OmniboxEditModel::SetInputInProgress(bool in_progress) {
 void OmniboxEditModel::Revert() {
   SetInputInProgress(false);
   paste_state_ = NONE;
-  InternalSetUserText(string16());
+  InternalSetUserText(base::string16());
   keyword_.clear();
   is_keyword_hint_ = false;
   has_temporary_text_ = false;
@@ -546,7 +546,7 @@ void OmniboxEditModel::StopAutocomplete() {
   autocomplete_controller()->Stop(true);
 }
 
-bool OmniboxEditModel::CanPasteAndGo(const string16& text) const {
+bool OmniboxEditModel::CanPasteAndGo(const base::string16& text) const {
   if (!view_->command_updater()->IsCommandEnabled(IDC_OPEN_CURRENT_URL))
     return false;
 
@@ -555,7 +555,7 @@ bool OmniboxEditModel::CanPasteAndGo(const string16& text) const {
   return match.destination_url.is_valid();
 }
 
-void OmniboxEditModel::PasteAndGo(const string16& text) {
+void OmniboxEditModel::PasteAndGo(const base::string16& text) {
   DCHECK(CanPasteAndGo(text));
   UMA_HISTOGRAM_COUNTS("Omnibox.PasteAndGo", 1);
 
@@ -567,7 +567,7 @@ void OmniboxEditModel::PasteAndGo(const string16& text) {
                    OmniboxPopupModel::kNoMatch);
 }
 
-bool OmniboxEditModel::IsPasteAndSearch(const string16& text) const {
+bool OmniboxEditModel::IsPasteAndSearch(const base::string16& text) const {
   AutocompleteMatch match;
   ClassifyStringForPasteAndGo(text, &match, NULL);
   return AutocompleteMatch::IsSearchType(match.type);
@@ -654,7 +654,7 @@ void OmniboxEditModel::OpenMatch(AutocompleteMatch match,
   autocomplete_controller()->UpdateMatchDestinationURL(
       elapsed_time_since_user_first_modified_omnibox, &match);
 
-  const string16& user_text =
+  const base::string16& user_text =
       user_input_in_progress_ ? user_text_ : permanent_text_;
   scoped_ptr<OmniboxNavigationObserver> observer(
       new OmniboxNavigationObserver(
@@ -763,7 +763,7 @@ void OmniboxEditModel::OpenMatch(AutocompleteMatch match,
   }
 
   // Get the current text before we call RevertAll() which will clear it.
-  string16 current_text = view_->GetText();
+  base::string16 current_text = view_->GetText();
 
   if (disposition != NEW_BACKGROUND_TAB) {
     base::AutoReset<bool> tmp(&in_revert_, true);
@@ -836,11 +836,11 @@ void OmniboxEditModel::AcceptTemporaryTextAsUserText() {
   delegate_->NotifySearchTabHelper(user_input_in_progress_, !in_revert_);
 }
 
-void OmniboxEditModel::ClearKeyword(const string16& visible_text) {
+void OmniboxEditModel::ClearKeyword(const base::string16& visible_text) {
   autocomplete_controller()->Stop(false);
   omnibox_controller_->ClearPopupKeywordMode();
 
-  const string16 window_text(keyword_ + visible_text);
+  const base::string16 window_text(keyword_ + visible_text);
 
   // Only reset the result if the edit text has changed since the
   // keyword was accepted, or if the popup is closed.
@@ -1001,9 +1001,9 @@ void OmniboxEditModel::OnUpOrDownKeyPressed(int count) {
 }
 
 void OmniboxEditModel::OnPopupDataChanged(
-    const string16& text,
+    const base::string16& text,
     GURL* destination_for_temporary_text_change,
-    const string16& keyword,
+    const base::string16& keyword,
     bool is_keyword_hint) {
   // The popup changed its data, the match in the controller is no longer valid.
   omnibox_controller_->InvalidateCurrentMatch();
@@ -1049,7 +1049,8 @@ void OmniboxEditModel::OnPopupDataChanged(
   if (inline_autocomplete_text_.empty())
     view_->OnInlineAutocompleteTextCleared();
 
-  string16 user_text = user_input_in_progress_ ? user_text_ : permanent_text_;
+  base::string16 user_text = user_input_in_progress_ ? user_text_
+                                                     : permanent_text_;
   if (keyword_state_changed && KeywordIsSelected()) {
     // If we reach here, the user most likely entered keyword mode by inserting
     // a space between a keyword name and a search string (as pressing space or
@@ -1090,8 +1091,8 @@ void OmniboxEditModel::OnPopupDataChanged(
     OnChanged();
 }
 
-bool OmniboxEditModel::OnAfterPossibleChange(const string16& old_text,
-                                             const string16& new_text,
+bool OmniboxEditModel::OnAfterPossibleChange(const base::string16& old_text,
+                                             const base::string16& new_text,
                                              size_t selection_start,
                                              size_t selection_end,
                                              bool selection_differs,
@@ -1201,7 +1202,7 @@ void OmniboxEditModel::OnCurrentMatchChanged() {
 
   // We store |keyword| and |is_keyword_hint| in temporary variables since
   // OnPopupDataChanged use their previous state to detect changes.
-  string16 keyword;
+  base::string16 keyword;
   bool is_keyword_hint;
   match.GetKeywordUIState(profile_, &keyword, &is_keyword_hint);
   if (popup_model())
@@ -1209,7 +1210,7 @@ void OmniboxEditModel::OnCurrentMatchChanged() {
   // OnPopupDataChanged() resets OmniboxController's |current_match_| early
   // on.  Therefore, copy match.inline_autocompletion to a temp to preserve
   // its value across the entire call.
-  const string16 inline_autocompletion(match.inline_autocompletion);
+  const base::string16 inline_autocompletion(match.inline_autocompletion);
   OnPopupDataChanged(inline_autocompletion, NULL, keyword, is_keyword_hint);
 }
 
@@ -1225,7 +1226,7 @@ bool OmniboxEditModel::query_in_progress() const {
   return !autocomplete_controller()->done();
 }
 
-void OmniboxEditModel::InternalSetUserText(const string16& text) {
+void OmniboxEditModel::InternalSetUserText(const base::string16& text) {
   user_text_ = text;
   just_deleted_text_ = false;
   inline_autocomplete_text_.clear();
@@ -1240,12 +1241,14 @@ void OmniboxEditModel::ClearPopupKeywordMode() const {
   omnibox_controller_->ClearPopupKeywordMode();
 }
 
-string16 OmniboxEditModel::DisplayTextFromUserText(const string16& text) const {
+string16 OmniboxEditModel::DisplayTextFromUserText(
+    const base::string16& text) const {
   return KeywordIsSelected() ?
       KeywordProvider::SplitReplacementStringFromInput(text, false) : text;
 }
 
-string16 OmniboxEditModel::UserTextFromDisplayText(const string16& text) const {
+string16 OmniboxEditModel::UserTextFromDisplayText(
+    const base::string16& text) const {
   return KeywordIsSelected() ? (keyword_ + char16(' ') + text) : text;
 }
 
@@ -1309,7 +1312,8 @@ void OmniboxEditModel::RevertTemporaryText(bool revert_popup) {
   view_->OnRevertTemporaryText();
 }
 
-bool OmniboxEditModel::MaybeAcceptKeywordBySpace(const string16& new_text) {
+bool OmniboxEditModel::MaybeAcceptKeywordBySpace(
+    const base::string16& new_text) {
   size_t keyword_length = new_text.length() - 1;
   return (paste_state_ == NONE) && is_keyword_hint_ && !keyword_.empty() &&
       inline_autocomplete_text_.empty() &&
@@ -1320,8 +1324,8 @@ bool OmniboxEditModel::MaybeAcceptKeywordBySpace(const string16& new_text) {
 }
 
 bool OmniboxEditModel::CreatedKeywordSearchByInsertingSpaceInMiddle(
-    const string16& old_text,
-    const string16& new_text,
+    const base::string16& old_text,
+    const base::string16& new_text,
     size_t caret_position) const {
   DCHECK_GE(new_text.length(), caret_position);
 
@@ -1341,7 +1345,7 @@ bool OmniboxEditModel::CreatedKeywordSearchByInsertingSpaceInMiddle(
   }
 
   // Then check if the text before the inserted space matches a keyword.
-  string16 keyword;
+  base::string16 keyword;
   TrimWhitespace(new_text.substr(0, space_position), TRIM_LEADING, &keyword);
   return !keyword.empty() && !autocomplete_controller()->keyword_provider()->
       GetKeywordForText(keyword).empty();
@@ -1386,7 +1390,7 @@ AutocompleteInput::PageClassification OmniboxEditModel::ClassifyPage() const {
 }
 
 void OmniboxEditModel::ClassifyStringForPasteAndGo(
-    const string16& text,
+    const base::string16& text,
     AutocompleteMatch* match,
     GURL* alternate_nav_url) const {
   DCHECK(match);
diff --git a/chrome/browser/ui/omnibox/omnibox_edit_model.h b/chrome/browser/ui/omnibox/omnibox_edit_model.h
index 0506598..dd5f04c 100644
--- a/chrome/browser/ui/omnibox/omnibox_edit_model.h
+++ b/chrome/browser/ui/omnibox/omnibox_edit_model.h
@@ -53,9 +53,9 @@ class OmniboxEditModel {
 
   struct State {
     State(bool user_input_in_progress,
-          const string16& user_text,
-          const string16& gray_text,
-          const string16& keyword,
+          const base::string16& user_text,
+          const base::string16& gray_text,
+          const base::string16& keyword,
           bool is_keyword_hint,
           bool url_replacement_enabled,
           OmniboxFocusState focus_state,
@@ -63,9 +63,9 @@ class OmniboxEditModel {
     ~State();
 
     bool user_input_in_progress;
-    const string16 user_text;
-    const string16 gray_text;
-    const string16 keyword;
+    const base::string16 user_text;
+    const base::string16 gray_text;
+    const base::string16 keyword;
     const bool is_keyword_hint;
     bool url_replacement_enabled;
     OmniboxFocusState focus_state;
@@ -114,7 +114,9 @@ class OmniboxEditModel {
 
   // Called when the user wants to export the entire current text as a URL.
   // Sets the url, and if known, the title and favicon.
-  void GetDataForURLExport(GURL* url, string16* title, gfx::Image* favicon);
+  void GetDataForURLExport(GURL* url,
+                           base::string16* title,
+                           gfx::Image* favicon);
 
   // Returns true if the current edit contents will be treated as a
   // URL/navigation, as opposed to a search.
@@ -131,7 +133,7 @@ class OmniboxEditModel {
   // is set to true and |url| set to the url to write.
   void AdjustTextForCopy(int sel_min,
                          bool is_all_selected,
-                         string16* text,
+                         base::string16* text,
                          GURL* url,
                          bool* write_url);
 
@@ -151,7 +153,7 @@ class OmniboxEditModel {
   GURL PermanentURL();
 
   // Sets the user_text_ to |text|.  Only the View should call this.
-  void SetUserText(const string16& text);
+  void SetUserText(const base::string16& text);
 
   // Commits the gray suggested text as if it's been input by the user.
   // Returns true if the text was committed.
@@ -174,14 +176,14 @@ class OmniboxEditModel {
   void StopAutocomplete();
 
   // Determines whether the user can "paste and go", given the specified text.
-  bool CanPasteAndGo(const string16& text) const;
+  bool CanPasteAndGo(const base::string16& text) const;
 
   // Navigates to the destination last supplied to CanPasteAndGo.
-  void PasteAndGo(const string16& text);
+  void PasteAndGo(const base::string16& text);
 
   // Returns true if this is a paste-and-search rather than paste-and-go (or
   // nothing).
-  bool IsPasteAndSearch(const string16& text) const;
+  bool IsPasteAndSearch(const base::string16& text) const;
 
   // Asks the browser to load the popup's currently selected item, using the
   // supplied disposition.  This may close the popup. If |for_drop| is true,
@@ -215,7 +217,7 @@ class OmniboxEditModel {
 
   // Accessors for keyword-related state (see comments on keyword_ and
   // is_keyword_hint_).
-  const string16& keyword() const { return keyword_; }
+  const base::string16& keyword() const { return keyword_; }
   bool is_keyword_hint() const { return is_keyword_hint_; }
 
   // Accepts the current keyword hint as a keyword. It always returns true for
@@ -229,7 +231,7 @@ class OmniboxEditModel {
 
   // Clears the current keyword.  |visible_text| is the (non-keyword) text
   // currently visible in the edit.
-  void ClearKeyword(const string16& visible_text);
+  void ClearKeyword(const base::string16& visible_text);
 
   // Returns the current autocomplete result.  This logic should in the future
   // live in AutocompleteController but resides here for now.  This method is
@@ -294,9 +296,9 @@ class OmniboxEditModel {
   //     or the currently selected keyword if |is_keyword_hint| is false (see
   //     comments on keyword_ and is_keyword_hint_).
   void OnPopupDataChanged(
-      const string16& text,
+      const base::string16& text,
       GURL* destination_for_temporary_text_change,
-      const string16& keyword,
+      const base::string16& keyword,
       bool is_keyword_hint);
 
   // Called by the OmniboxView after something changes, with details about what
@@ -308,8 +310,8 @@ class OmniboxEditModel {
   // If |allow_keyword_ui_change| is false then the change should not affect
   // keyword ui state, even if the text matches a keyword exactly. This value
   // may be false when the user is composing a text with an IME.
-  bool OnAfterPossibleChange(const string16& old_text,
-                             const string16& new_text,
+  bool OnAfterPossibleChange(const base::string16& old_text,
+                             const base::string16& new_text,
                              size_t selection_start,
                              size_t selection_end,
                              bool selection_differs,
@@ -364,7 +366,7 @@ class OmniboxEditModel {
   bool query_in_progress() const;
 
   // Called whenever user_text_ should change.
-  void InternalSetUserText(const string16& text);
+  void InternalSetUserText(const base::string16& text);
 
   // Returns true if a keyword is selected.
   bool KeywordIsSelected() const;
@@ -375,8 +377,8 @@ class OmniboxEditModel {
   // Conversion between user text and display text. User text is the text the
   // user has input. Display text is the text being shown in the edit. The
   // two are different if a keyword is selected.
-  string16 DisplayTextFromUserText(const string16& text) const;
-  string16 UserTextFromDisplayText(const string16& text) const;
+  base::string16 DisplayTextFromUserText(const base::string16& text) const;
+  base::string16 UserTextFromDisplayText(const base::string16& text) const;
 
   // If there's a selected match, copies it into |match|. Else, returns the
   // default match for the current text, as well as the alternate nav URL, if
@@ -394,13 +396,13 @@ class OmniboxEditModel {
   //   foo| -> foo |      (a space was appended to a keyword)
   //   foo[bar] -> foo |  (a space replaced other text after a keyword)
   // Returns true if the current keyword is accepted.
-  bool MaybeAcceptKeywordBySpace(const string16& new_text);
+  bool MaybeAcceptKeywordBySpace(const base::string16& new_text);
 
   // Checks whether the user inserted a space into |old_text| and by doing so
   // created a |new_text| that looks like "<keyword> <search phrase>".
   bool CreatedKeywordSearchByInsertingSpaceInMiddle(
-      const string16& old_text,
-      const string16& new_text,
+      const base::string16& old_text,
+      const base::string16& new_text,
       size_t caret_position) const;
 
   // Checks if a given character is a valid space character for accepting
@@ -415,7 +417,7 @@ class OmniboxEditModel {
 
   // Sets |match| and |alternate_nav_url| based on classifying |text|.
   // |alternate_nav_url| may be NULL.
-  void ClassifyStringForPasteAndGo(const string16& text,
+  void ClassifyStringForPasteAndGo(const base::string16& text,
                                    AutocompleteMatch* match,
                                    GURL* alternate_nav_url) const;
 
@@ -441,7 +443,7 @@ class OmniboxEditModel {
   FocusSource focus_source_;
 
   // The URL of the currently displayed page.
-  string16 permanent_text_;
+  base::string16 permanent_text_;
 
   // This flag is true when the user has modified the contents of the edit, but
   // not yet accepted them.  We use this to determine when we need to save
@@ -452,7 +454,7 @@ class OmniboxEditModel {
 
   // The text that the user has entered.  This does not include inline
   // autocomplete text that has not yet been accepted.
-  string16 user_text_;
+  base::string16 user_text_;
 
   // We keep track of when the user last focused on the omnibox.
   base::TimeTicks last_omnibox_focus_;
@@ -482,7 +484,7 @@ class OmniboxEditModel {
   // simply ask the popup for the desired URL directly.  As a result, the
   // contents of this variable only need to be updated when the popup is closed
   // but user_input_in_progress_ is not being cleared.
-  string16 url_for_remembered_user_selection_;
+  base::string16 url_for_remembered_user_selection_;
 
   // Inline autocomplete is allowed if the user has not just deleted text, and
   // no temporary text is showing.  In this case, inline_autocomplete_text_ is
@@ -492,7 +494,7 @@ class OmniboxEditModel {
   // text (actions that close the popup should either accept the text, convert
   // it to a normal selection, or change the edit entirely).
   bool just_deleted_text_;
-  string16 inline_autocomplete_text_;
+  base::string16 inline_autocomplete_text_;
 
   // Used by OnPopupDataChanged to keep track of whether there is currently a
   // temporary text.
@@ -525,7 +527,7 @@ class OmniboxEditModel {
   // selected keyword, or just some input text that looks like a keyword (so we
   // can show a hint to press <tab>).  This is the keyword in either case;
   // is_keyword_hint_ (below) distinguishes the two cases.
-  string16 keyword_;
+  base::string16 keyword_;
 
   // True if the keyword associated with this match is merely a hint, i.e. the
   // user hasn't actually selected a keyword yet.  When this is true, we can use
diff --git a/chrome/browser/ui/omnibox/omnibox_navigation_observer.cc b/chrome/browser/ui/omnibox/omnibox_navigation_observer.cc
index b7b9057..98750ff 100644
--- a/chrome/browser/ui/omnibox/omnibox_navigation_observer.cc
+++ b/chrome/browser/ui/omnibox/omnibox_navigation_observer.cc
@@ -52,7 +52,7 @@ bool IsValidNavigation(const GURL& original_url, const GURL& final_url) {
 
 OmniboxNavigationObserver::OmniboxNavigationObserver(
     Profile* profile,
-    const string16& text,
+    const base::string16& text,
     const AutocompleteMatch& match,
     const AutocompleteMatch& alternate_nav_match)
     : text_(text),
diff --git a/chrome/browser/ui/omnibox/omnibox_navigation_observer.h b/chrome/browser/ui/omnibox/omnibox_navigation_observer.h
index 1d0a6bc..f4a795c 100644
--- a/chrome/browser/ui/omnibox/omnibox_navigation_observer.h
+++ b/chrome/browser/ui/omnibox/omnibox_navigation_observer.h
@@ -54,7 +54,7 @@ class OmniboxNavigationObserver : public content::NotificationObserver,
   };
 
   OmniboxNavigationObserver(Profile* profile,
-                            const string16& text,
+                            const base::string16& text,
                             const AutocompleteMatch& match,
                             const AutocompleteMatch& alternate_nav_match);
   virtual ~OmniboxNavigationObserver();
@@ -94,7 +94,7 @@ class OmniboxNavigationObserver : public content::NotificationObserver,
   // the alternate nav infobar if necessary, and deletes |this|.
   void OnAllLoadingFinished();
 
-  const string16 text_;
+  const base::string16 text_;
   const AutocompleteMatch match_;
   const AutocompleteMatch alternate_nav_match_;
   scoped_refptr<history::ShortcutsBackend> shortcuts_backend_;  // May be NULL
diff --git a/chrome/browser/ui/omnibox/omnibox_popup_model.cc b/chrome/browser/ui/omnibox/omnibox_popup_model.cc
index 2f782cd..d7d88ba 100644
--- a/chrome/browser/ui/omnibox/omnibox_popup_model.cc
+++ b/chrome/browser/ui/omnibox/omnibox_popup_model.cc
@@ -106,7 +106,7 @@ void OmniboxPopupModel::SetSelectedLine(size_t line,
   // Update the edit with the new data for this match.
   // TODO(pkasting): If |selected_line_| moves to the controller, this can be
   // eliminated and just become a call to the observer on the edit.
-  string16 keyword;
+  base::string16 keyword;
   bool is_keyword_hint;
   match.GetKeywordUIState(edit_model_->profile(), &keyword, &is_keyword_hint);
 
diff --git a/chrome/browser/ui/omnibox/omnibox_view.cc b/chrome/browser/ui/omnibox/omnibox_view.cc
index 0387b1e..79cafa0 100644
--- a/chrome/browser/ui/omnibox/omnibox_view.cc
+++ b/chrome/browser/ui/omnibox/omnibox_view.cc
@@ -16,24 +16,24 @@
 #include "ui/base/clipboard/clipboard.h"
 
 // static
-string16 OmniboxView::StripJavascriptSchemas(const string16& text) {
-  const string16 kJsPrefix(ASCIIToUTF16(content::kJavaScriptScheme) +
+string16 OmniboxView::StripJavascriptSchemas(const base::string16& text) {
+  const base::string16 kJsPrefix(ASCIIToUTF16(content::kJavaScriptScheme) +
                            ASCIIToUTF16(":"));
-  string16 out(text);
+  base::string16 out(text);
   while (StartsWith(out, kJsPrefix, false))
     TrimWhitespace(out.substr(kJsPrefix.length()), TRIM_LEADING, &out);
   return out;
 }
 
 // static
-string16 OmniboxView::SanitizeTextForPaste(const string16& text) {
+string16 OmniboxView::SanitizeTextForPaste(const base::string16& text) {
   // Check for non-newline whitespace; if found, collapse whitespace runs down
   // to single spaces.
   // TODO(shess): It may also make sense to ignore leading or
   // trailing whitespace when making this determination.
   for (size_t i = 0; i < text.size(); ++i) {
     if (IsWhitespace(text[i]) && text[i] != '\n' && text[i] != '\r') {
-      const string16 collapsed = CollapseWhitespace(text, false);
+      const base::string16 collapsed = CollapseWhitespace(text, false);
       // If the user is pasting all-whitespace, paste a single space
       // rather than nothing, since pasting nothing feels broken.
       return collapsed.empty() ?
@@ -51,7 +51,7 @@ string16 OmniboxView::GetClipboardText() {
   ui::Clipboard* clipboard = ui::Clipboard::GetForCurrentThread();
   if (clipboard->IsFormatAvailable(ui::Clipboard::GetPlainTextWFormatType(),
                                    ui::CLIPBOARD_TYPE_COPY_PASTE)) {
-    string16 text;
+    base::string16 text;
     clipboard->ReadText(ui::CLIPBOARD_TYPE_COPY_PASTE, &text);
     return SanitizeTextForPaste(text);
   }
@@ -73,7 +73,7 @@ string16 OmniboxView::GetClipboardText() {
       return StripJavascriptSchemas(UTF8ToUTF16(url.spec()));
   }
 
-  return string16();
+  return base::string16();
 }
 
 OmniboxView::~OmniboxView() {
@@ -102,12 +102,12 @@ int OmniboxView::GetIcon() const {
       model_->CurrentTextType() : AutocompleteMatchType::URL_WHAT_YOU_TYPED);
 }
 
-void OmniboxView::SetUserText(const string16& text) {
+void OmniboxView::SetUserText(const base::string16& text) {
   SetUserText(text, text, true);
 }
 
-void OmniboxView::SetUserText(const string16& text,
-                              const string16& display_text,
+void OmniboxView::SetUserText(const base::string16& text,
+                              const base::string16& display_text,
                               bool update_popup) {
   if (model_.get())
     model_->SetUserText(text);
diff --git a/chrome/browser/ui/omnibox/omnibox_view.h b/chrome/browser/ui/omnibox/omnibox_view.h
index 1899590..d56d120 100644
--- a/chrome/browser/ui/omnibox/omnibox_view.h
+++ b/chrome/browser/ui/omnibox/omnibox_view.h
@@ -86,7 +86,7 @@ class OmniboxView {
   // Returns the current text of the edit control, which could be the
   // "temporary" text set by the popup, the "permanent" text set by the
   // browser, or just whatever the user has currently typed.
-  virtual string16 GetText() const = 0;
+  virtual base::string16 GetText() const = 0;
 
   // |true| if the user is in the process of editing the field, or if
   // the field is empty.
@@ -98,14 +98,14 @@ class OmniboxView {
   // The user text is the text the user has manually keyed in.  When present,
   // this is shown in preference to the permanent text; hitting escape will
   // revert to the permanent text.
-  void SetUserText(const string16& text);
-  virtual void SetUserText(const string16& text,
-                           const string16& display_text,
+  void SetUserText(const base::string16& text);
+  virtual void SetUserText(const base::string16& text,
+                           const base::string16& display_text,
                            bool update_popup);
 
   // Sets the window text and the caret position. |notify_text_changed| is true
   // if the model should be notified of the change.
-  virtual void SetWindowTextAndCaretPos(const string16& text,
+  virtual void SetWindowTextAndCaretPos(const base::string16& text,
                                         size_t caret_pos,
                                         bool update_popup,
                                         bool notify_text_changed) = 0;
@@ -164,7 +164,7 @@ class OmniboxView {
   // when there wasn't previously a temporary text and thus we need to save off
   // the user's existing selection. |notify_text_changed| is true if the model
   // should be notified of the change.
-  virtual void OnTemporaryTextMaybeChanged(const string16& display_text,
+  virtual void OnTemporaryTextMaybeChanged(const base::string16& display_text,
                                            bool save_original_selection,
                                            bool notify_text_changed) = 0;
 
@@ -173,7 +173,7 @@ class OmniboxView {
   // the user input portion of that (so, up to but not including the inline
   // autocompletion).  Returns whether the display text actually changed.
   virtual bool OnInlineAutocompleteTextMaybeChanged(
-      const string16& display_text, size_t user_text_length) = 0;
+      const base::string16& display_text, size_t user_text_length) = 0;
 
   // Called when the inline autocomplete text in the model has been cleared.
   virtual void OnInlineAutocompleteTextCleared() = 0;
@@ -201,10 +201,10 @@ class OmniboxView {
   virtual gfx::NativeView GetRelativeWindowForPopup() const = 0;
 
   // Shows |input| as gray suggested text after what the user has typed.
-  virtual void SetGrayTextAutocompletion(const string16& input) = 0;
+  virtual void SetGrayTextAutocompletion(const base::string16& input) = 0;
 
   // Returns the current gray suggested text.
-  virtual string16 GetGrayTextAutocompletion() const = 0;
+  virtual base::string16 GetGrayTextAutocompletion() const = 0;
 
   // Returns the width in pixels needed to display the current text. The
   // returned value includes margins.
@@ -232,7 +232,7 @@ class OmniboxView {
 #endif
 
   // Returns |text| with any leading javascript schemas stripped.
-  static string16 StripJavascriptSchemas(const string16& text);
+  static base::string16 StripJavascriptSchemas(const base::string16& text);
 
   // First, calls StripJavascriptSchemas().  Then automatically collapses
   // internal whitespace as follows:
@@ -241,12 +241,12 @@ class OmniboxView {
   // etc. So all newlines are removed.
   // * Otherwise, users may be pasting in search data, e.g. street addresses. In
   // this case, runs of whitespace are collapsed down to single spaces.
-  static string16 SanitizeTextForPaste(const string16& text);
+  static base::string16 SanitizeTextForPaste(const base::string16& text);
 
   // Returns the current clipboard contents as a string that can be pasted in.
   // In addition to just getting CF_UNICODETEXT out, this can also extract URLs
   // from bookmarks on the clipboard.
-  static string16 GetClipboardText();
+  static base::string16 GetClipboardText();
 
  protected:
   OmniboxView(Profile* profile,
diff --git a/chrome/browser/ui/omnibox/omnibox_view_browsertest.cc b/chrome/browser/ui/omnibox/omnibox_view_browsertest.cc
index 7023d45..69aa2ba 100644
--- a/chrome/browser/ui/omnibox/omnibox_view_browsertest.cc
+++ b/chrome/browser/ui/omnibox/omnibox_view_browsertest.cc
@@ -128,7 +128,7 @@ std::string GetPrimarySelectionText() {
 #endif
 
 // Stores the given text to clipboard.
-void SetClipboardText(const string16& text) {
+void SetClipboardText(const base::string16& text) {
   ui::Clipboard* clipboard = ui::Clipboard::GetForCurrentThread();
   ui::ScopedClipboardWriter writer(clipboard, ui::CLIPBOARD_TYPE_COPY_PASTE);
   writer.WriteText(text);
@@ -304,7 +304,7 @@ class OmniboxViewTest : public InProcessBrowserTest,
                                         entry.typed_count, time, false,
                                         history::SOURCE_BROWSED);
     if (entry.starred)
-      bookmark_utils::AddIfNotBookmarked(bookmark_model, url, string16());
+      bookmark_utils::AddIfNotBookmarked(bookmark_model, url, base::string16());
     // Wait at least for the AddPageWithDetails() call to finish.
     {
       content::NotificationRegistrar registrar;
@@ -553,7 +553,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_Escape) {
   OmniboxView* omnibox_view = NULL;
   ASSERT_NO_FATAL_FAILURE(GetOmniboxView(&omnibox_view));
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
   EXPECT_FALSE(old_text.empty());
   EXPECT_TRUE(omnibox_view->IsSelectAll());
 
@@ -716,7 +716,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_EscapeToDefaultMatch) {
   ASSERT_NO_FATAL_FAILURE(WaitForAutocompleteControllerDone());
   ASSERT_TRUE(popup_model->IsOpen());
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
 
   // Make sure inline autocomplete is triggerred.
   EXPECT_GT(old_text.length(), arraysize(kInlineAutocompleteText) - 1);
@@ -754,7 +754,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_BasicTextOperations) {
   OmniboxView* omnibox_view = NULL;
   ASSERT_NO_FATAL_FAILURE(GetOmniboxView(&omnibox_view));
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
   EXPECT_EQ(UTF8ToUTF16(content::kAboutBlankURL), old_text);
   EXPECT_TRUE(omnibox_view->IsSelectAll());
 
@@ -821,7 +821,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_AcceptKeywordBySpace) {
   OmniboxView* omnibox_view = NULL;
   ASSERT_NO_FATAL_FAILURE(GetOmniboxView(&omnibox_view));
 
-  string16 search_keyword(ASCIIToUTF16(kSearchKeyword));
+  base::string16 search_keyword(ASCIIToUTF16(kSearchKeyword));
 
   // Trigger keyword hint mode.
   ASSERT_NO_FATAL_FAILURE(SendKeySequence(kSearchKeywordKeys));
@@ -998,7 +998,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_AcceptKeywordBySpace) {
   ASSERT_NO_FATAL_FAILURE(SendKey(ui::VKEY_E, 0));
   ASSERT_NO_FATAL_FAILURE(WaitForAutocompleteControllerDone());
   ASSERT_TRUE(popup_model->IsOpen());
-  string16 search_keyword2(ASCIIToUTF16(kSearchKeyword2));
+  base::string16 search_keyword2(ASCIIToUTF16(kSearchKeyword2));
   while ((omnibox_view->GetText() != search_keyword2) &&
          (popup_model->selected_line() < popup_model->result().size() - 1))
     omnibox_view->model()->OnUpOrDownKeyPressed(1);
@@ -1089,7 +1089,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_DeleteItem) {
   OmniboxPopupModel* popup_model = omnibox_view->model()->popup_model();
   ASSERT_TRUE(popup_model);
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
 
   // Input something that can match history items.
   omnibox_view->SetUserText(ASCIIToUTF16("site.com/p"));
@@ -1102,7 +1102,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_DeleteItem) {
   ASSERT_TRUE(popup_model->IsOpen());
   ASSERT_GE(popup_model->result().size(), 3U);
 
-  string16 user_text = omnibox_view->GetText();
+  base::string16 user_text = omnibox_view->GetText();
   ASSERT_EQ(ASCIIToUTF16("site.com/p"), user_text);
   omnibox_view->SelectAll(true);
   ASSERT_TRUE(omnibox_view->IsSelectAll());
@@ -1111,7 +1111,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_DeleteItem) {
   size_t default_line = popup_model->selected_line();
   omnibox_view->model()->OnUpOrDownKeyPressed(1);
   ASSERT_EQ(default_line + 1, popup_model->selected_line());
-  string16 selected_text =
+  base::string16 selected_text =
       popup_model->result().match_at(default_line + 1).fill_into_edit;
   // Temporary text is shown.
   ASSERT_EQ(selected_text, omnibox_view->GetText());
@@ -1183,7 +1183,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_TabAcceptKeyword) {
   OmniboxView* omnibox_view = NULL;
   ASSERT_NO_FATAL_FAILURE(GetOmniboxView(&omnibox_view));
 
-  string16 text = ASCIIToUTF16(kSearchKeyword);
+  base::string16 text = ASCIIToUTF16(kSearchKeyword);
 
   // Trigger keyword hint mode.
   ASSERT_NO_FATAL_FAILURE(SendKeySequence(kSearchKeywordKeys));
@@ -1288,7 +1288,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, MAYBE_TabTraverseResultsTest) {
   ASSERT_NO_FATAL_FAILURE(WaitForAutocompleteControllerDone());
 
   // Trigger keyword mode by tab.
-  string16 text = ASCIIToUTF16(kSearchKeyword);
+  base::string16 text = ASCIIToUTF16(kSearchKeyword);
   ASSERT_NO_FATAL_FAILURE(SendKey(ui::VKEY_TAB, 0));
   ASSERT_FALSE(omnibox_view->model()->is_keyword_hint());
   ASSERT_EQ(text, omnibox_view->model()->keyword());
@@ -1371,7 +1371,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest,
   ASSERT_NO_FATAL_FAILURE(WaitForAutocompleteControllerDone());
   ASSERT_TRUE(popup_model->IsOpen());
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
 
   // Make sure inline autocomplete is triggerred.
   EXPECT_GT(old_text.length(), arraysize(kInlineAutocompleteText) - 1);
@@ -1391,7 +1391,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, UndoRedo) {
   OmniboxView* omnibox_view = NULL;
   ASSERT_NO_FATAL_FAILURE(GetOmniboxView(&omnibox_view));
 
-  string16 old_text = omnibox_view->GetText();
+  base::string16 old_text = omnibox_view->GetText();
   EXPECT_EQ(UTF8ToUTF16(content::kAboutBlankURL), old_text);
   EXPECT_TRUE(omnibox_view->IsSelectAll());
 
@@ -1474,7 +1474,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, DoesNotUpdateAutocompleteOnBlur) {
   size_t start, end;
   omnibox_view->GetSelectionBounds(&start, &end);
   EXPECT_TRUE(start != end);
-  string16 old_autocomplete_text =
+  base::string16 old_autocomplete_text =
       omnibox_view->model()->autocomplete_controller()->input().text();
 
   // Unfocus the omnibox. This should clear the text field selection and
@@ -1600,7 +1600,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, CopyURLToClipboard) {
 
   // These platforms should read bookmark format.
 #if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(OS_MACOSX)
-  string16 title;
+  base::string16 title;
   std::string url;
   clipboard->ReadBookmark(&title, &url);
   EXPECT_EQ(target_url, url);
@@ -1646,7 +1646,7 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest, CutURLToClipboard) {
 
   // These platforms should read bookmark format.
 #if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(OS_MACOSX)
-  string16 title;
+  base::string16 title;
   std::string url;
   clipboard->ReadBookmark(&title, &url);
   EXPECT_EQ(target_url, url);
@@ -1790,9 +1790,9 @@ IN_PROC_BROWSER_TEST_F(OmniboxViewTest,
   scoped_ptr<ToolbarModel> toolbar_model(test_toolbar_model);
   browser()->swap_toolbar_models(&toolbar_model);
 
-  string16 url_a(ASCIIToUTF16("http://www.a.com/"));
-  string16 url_b(ASCIIToUTF16("http://www.b.com/"));
-  string16 url_c(ASCIIToUTF16("http://www.c.com/"));
+  base::string16 url_a(ASCIIToUTF16("http://www.a.com/"));
+  base::string16 url_b(ASCIIToUTF16("http://www.b.com/"));
+  base::string16 url_c(ASCIIToUTF16("http://www.c.com/"));
   chrome::FocusLocationBar(browser());
   test_toolbar_model->set_text(url_a);
   omnibox_view->Update();
diff --git a/chrome/browser/ui/omnibox/omnibox_view_unittest.cc b/chrome/browser/ui/omnibox/omnibox_view_unittest.cc
index d2dc86b..5056e76 100644
--- a/chrome/browser/ui/omnibox/omnibox_view_unittest.cc
+++ b/chrome/browser/ui/omnibox/omnibox_view_unittest.cc
@@ -46,20 +46,20 @@ TEST_F(OmniboxViewTest, TestStripSchemasUnsafeForPaste) {
 
 TEST_F(OmniboxViewTest, SanitizeTextForPaste) {
   // Broken URL has newlines stripped.
-  const string16 kWrappedURL(ASCIIToUTF16(
+  const base::string16 kWrappedURL(ASCIIToUTF16(
       "http://www.chromium.org/developers/testing/chromium-\n"
       "build-infrastructure/tour-of-the-chromium-buildbot"));
 
-  const string16 kFixedURL(ASCIIToUTF16(
+  const base::string16 kFixedURL(ASCIIToUTF16(
       "http://www.chromium.org/developers/testing/chromium-"
       "build-infrastructure/tour-of-the-chromium-buildbot"));
   EXPECT_EQ(kFixedURL, OmniboxView::SanitizeTextForPaste(kWrappedURL));
 
   // Multi-line address is converted to a single-line address.
-  const string16 kWrappedAddress(ASCIIToUTF16(
+  const base::string16 kWrappedAddress(ASCIIToUTF16(
       "1600 Amphitheatre Parkway\nMountain View, CA"));
 
-  const string16 kFixedAddress(ASCIIToUTF16(
+  const base::string16 kFixedAddress(ASCIIToUTF16(
       "1600 Amphitheatre Parkway Mountain View, CA"));
   EXPECT_EQ(kFixedAddress, OmniboxView::SanitizeTextForPaste(kWrappedAddress));
 }
@@ -67,7 +67,7 @@ TEST_F(OmniboxViewTest, SanitizeTextForPaste) {
 TEST_F(OmniboxViewTest, GetClipboardText) {
   ui::Clipboard* clipboard = ui::Clipboard::GetForCurrentThread();
 
-  const string16 kPlainText(ASCIIToUTF16("test text"));
+  const base::string16 kPlainText(ASCIIToUTF16("test text"));
   const std::string kURL("http://www.example.com/");
 
   // Can we pull straight text off the clipboard?
@@ -79,8 +79,8 @@ TEST_F(OmniboxViewTest, GetClipboardText) {
   EXPECT_EQ(kPlainText, OmniboxView::GetClipboardText());
 
   // Can we pull a string consists of white-space?
-  const string16 kSpace6(ASCIIToUTF16("      "));
-  const string16 kSpace1(ASCIIToUTF16(" "));
+  const base::string16 kSpace6(ASCIIToUTF16("      "));
+  const base::string16 kSpace1(ASCIIToUTF16(" "));
   {
     ui::ScopedClipboardWriter clipboard_writer(clipboard,
                                                ui::CLIPBOARD_TYPE_COPY_PASTE);
@@ -100,7 +100,7 @@ TEST_F(OmniboxViewTest, GetClipboardText) {
   // Bookmark clipboard apparently not supported on Linux.
   // See TODO on ClipboardText.BookmarkTest.
 #if !defined(OS_POSIX) || defined(OS_MACOSX)
-  const string16 kTitle(ASCIIToUTF16("The Example Company"));
+  const base::string16 kTitle(ASCIIToUTF16("The Example Company"));
   // Can we pull a bookmark off the clipboard?
   {
     ui::ScopedClipboardWriter clipboard_writer(clipboard,
@@ -121,7 +121,7 @@ TEST_F(OmniboxViewTest, GetClipboardText) {
 
   // Do we get nothing if there is neither text nor a bookmark?
   {
-    const string16 kMarkup(ASCIIToUTF16("<strong>Hi!</string>"));
+    const base::string16 kMarkup(ASCIIToUTF16("<strong>Hi!</string>"));
     ui::ScopedClipboardWriter clipboard_writer(clipboard,
                                                ui::CLIPBOARD_TYPE_COPY_PASTE);
     clipboard_writer.WriteHTML(kMarkup, kURL);
diff --git a/chrome/browser/ui/panels/native_panel_stack_window.h b/chrome/browser/ui/panels/native_panel_stack_window.h
index a8c63ca..ee54173 100644
--- a/chrome/browser/ui/panels/native_panel_stack_window.h
+++ b/chrome/browser/ui/panels/native_panel_stack_window.h
@@ -18,7 +18,7 @@ class Vector2d;
 class NativePanelStackWindowDelegate {
  public:
   // Returns the title representing the whole stack.
-  virtual string16 GetTitle() const = 0;
+  virtual base::string16 GetTitle() const = 0;
 
   // Returns the icon denoting the whole stack.
   virtual gfx::Image GetIcon() const = 0;
diff --git a/chrome/browser/ui/panels/panel.cc b/chrome/browser/ui/panels/panel.cc
index 16b1013..b011d63 100644
--- a/chrome/browser/ui/panels/panel.cc
+++ b/chrome/browser/ui/panels/panel.cc
@@ -748,9 +748,9 @@ bool Panel::ExecuteCommandIfEnabled(int id) {
   return false;
 }
 
-string16 Panel::GetWindowTitle() const {
+base::string16 Panel::GetWindowTitle() const {
   content::WebContents* contents = GetWebContents();
-  string16 title;
+  base::string16 title;
 
   // |contents| can be NULL during the window's creation.
   if (contents) {
@@ -891,8 +891,9 @@ void Panel::UpdateAppIcon() {
 void Panel::FormatTitleForDisplay(string16* title) {
   size_t current_index = 0;
   size_t match_index;
-  while ((match_index = title->find(L'\n', current_index)) != string16::npos) {
-    title->replace(match_index, 1, string16());
+  while ((match_index = title->find(L'\n', current_index)) !=
+         base::string16::npos) {
+    title->replace(match_index, 1, base::string16());
     current_index = match_index;
   }
 }
diff --git a/chrome/browser/ui/panels/panel.h b/chrome/browser/ui/panels/panel.h
index 3e5bde5..5a84428 100644
--- a/chrome/browser/ui/panels/panel.h
+++ b/chrome/browser/ui/panels/panel.h
@@ -276,7 +276,7 @@ class Panel : public ui::BaseWindow,
   bool ExecuteCommandIfEnabled(int id);
 
   // Gets the title of the window from the web contents.
-  string16 GetWindowTitle() const;
+  base::string16 GetWindowTitle() const;
 
   // Gets the Favicon of the web contents.
   gfx::Image GetCurrentPageIcon() const;
diff --git a/chrome/browser/ui/panels/panel_browsertest.cc b/chrome/browser/ui/panels/panel_browsertest.cc
index 0549d50..80ef7a8 100644
--- a/chrome/browser/ui/panels/panel_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_browsertest.cc
@@ -1440,8 +1440,8 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, OnBeforeUnloadOnClose) {
   PanelManager* panel_manager = PanelManager::GetInstance();
   EXPECT_EQ(0, panel_manager->num_panels()); // No panels initially.
 
-  const string16 title_first_close = UTF8ToUTF16("TitleFirstClose");
-  const string16 title_second_close = UTF8ToUTF16("TitleSecondClose");
+  const base::string16 title_first_close = UTF8ToUTF16("TitleFirstClose");
+  const base::string16 title_second_close = UTF8ToUTF16("TitleSecondClose");
 
   // Create a test panel with web contents loaded.
   CreatePanelParams params("PanelTest1", gfx::Rect(0, 0, 300, 300),
diff --git a/chrome/browser/ui/panels/stacked_panel_collection.cc b/chrome/browser/ui/panels/stacked_panel_collection.cc
index 92e4aa6..ca8c28d 100644
--- a/chrome/browser/ui/panels/stacked_panel_collection.cc
+++ b/chrome/browser/ui/panels/stacked_panel_collection.cc
@@ -141,7 +141,7 @@ void StackedPanelCollection::RefreshLayoutWithTopPanelStartingAt(
 
 string16 StackedPanelCollection::GetTitle() const {
   if (panels_.empty())
-    return string16();
+    return base::string16();
 
   Panel* panel = panels_.front();
   const extensions::Extension* extension = panel->GetExtension();
diff --git a/chrome/browser/ui/panels/stacked_panel_collection.h b/chrome/browser/ui/panels/stacked_panel_collection.h
index 147abcb..790910a 100644
--- a/chrome/browser/ui/panels/stacked_panel_collection.h
+++ b/chrome/browser/ui/panels/stacked_panel_collection.h
@@ -104,7 +104,7 @@ class StackedPanelCollection : public PanelCollection,
   };
 
   // Overridden from PanelBoundsBatchUpdateObserver:
-  virtual string16 GetTitle() const OVERRIDE;
+  virtual base::string16 GetTitle() const OVERRIDE;
   virtual gfx::Image GetIcon() const OVERRIDE;
   virtual void PanelBoundsBatchUpdateCompleted() OVERRIDE;
 
diff --git a/chrome/browser/ui/process_singleton_dialog_linux.h b/chrome/browser/ui/process_singleton_dialog_linux.h
index c80aa30..ffea405 100644
--- a/chrome/browser/ui/process_singleton_dialog_linux.h
+++ b/chrome/browser/ui/process_singleton_dialog_linux.h
@@ -12,7 +12,7 @@
 // started by that point in the startup process.
 
 // Shows the dialog, and returns once the dialog has been closed.
-bool ShowProcessSingletonDialog(const string16& message,
-                                const string16& relaunch_text);
+bool ShowProcessSingletonDialog(const base::string16& message,
+                                const base::string16& relaunch_text);
 
 #endif  // CHROME_BROWSER_UI_PROCESS_SINGLETON_DIALOG_LINUX_H_
diff --git a/chrome/browser/ui/protocol_dialog_delegate.h b/chrome/browser/ui/protocol_dialog_delegate.h
index 87140c1..48ff0b2 100644
--- a/chrome/browser/ui/protocol_dialog_delegate.h
+++ b/chrome/browser/ui/protocol_dialog_delegate.h
@@ -27,9 +27,9 @@ class ProtocolDialogDelegate {
   // dialog is checked.
   virtual void DoCancel(const GURL& url, bool dont_block) const = 0;
 
-  virtual string16 GetMessageText() const = 0;
-  virtual string16 GetCheckboxText() const = 0;
-  virtual string16 GetTitleText() const = 0;
+  virtual base::string16 GetMessageText() const = 0;
+  virtual base::string16 GetCheckboxText() const = 0;
+  virtual base::string16 GetTitleText() const = 0;
 
   const GURL& url() const { return url_; }
 
diff --git a/chrome/browser/ui/screen_capture_notification_ui.h b/chrome/browser/ui/screen_capture_notification_ui.h
index b714c2d..c3d3dbe 100644
--- a/chrome/browser/ui/screen_capture_notification_ui.h
+++ b/chrome/browser/ui/screen_capture_notification_ui.h
@@ -17,7 +17,8 @@ class ScreenCaptureNotificationUI : public content::MediaStreamUI {
 
   // Creates platform-specific screen capture notification UI. |text| specifies
   // the text that should be shown in the notification.
-  static scoped_ptr<ScreenCaptureNotificationUI> Create(const string16& text);
+  static scoped_ptr<ScreenCaptureNotificationUI> Create(
+      const base::string16& text);
 };
 
 #endif  // CHROME_BROWSER_UI_SCREEN_CAPTURE_NOTIFICATION_UI_H_
diff --git a/chrome/browser/ui/screen_capture_notification_ui_stub.cc b/chrome/browser/ui/screen_capture_notification_ui_stub.cc
index 83a98b8..5dfb1a8 100644
--- a/chrome/browser/ui/screen_capture_notification_ui_stub.cc
+++ b/chrome/browser/ui/screen_capture_notification_ui_stub.cc
@@ -19,7 +19,7 @@ class ScreenCaptureNotificationUIStub : public ScreenCaptureNotificationUI {
 
 // static
 scoped_ptr<ScreenCaptureNotificationUI> ScreenCaptureNotificationUI::Create(
-    const string16& title) {
+    const base::string16& title) {
   return scoped_ptr<ScreenCaptureNotificationUI>(
       new ScreenCaptureNotificationUIStub());
 }
diff --git a/chrome/browser/ui/search/instant_controller.cc b/chrome/browser/ui/search/instant_controller.cc
index c208a26..f3a2a4f 100644
--- a/chrome/browser/ui/search/instant_controller.cc
+++ b/chrome/browser/ui/search/instant_controller.cc
@@ -53,7 +53,7 @@ bool IsContentsFrom(const InstantPage* page,
 // supplied |search_terms|. Sets the |search_terms| on the transient entry for
 // search terms extraction to work correctly.
 void EnsureSearchTermsAreSet(content::WebContents* contents,
-                             const string16& search_terms) {
+                             const base::string16& search_terms) {
   content::NavigationController* controller = &contents->GetController();
 
   // If search terms are already correct or there is already a transient entry
@@ -142,7 +142,7 @@ void InstantController::InstantPageLoadFailed(content::WebContents* contents) {
   RedirectToLocalNTP(contents);
 }
 
-bool InstantController::SubmitQuery(const string16& search_terms) {
+bool InstantController::SubmitQuery(const base::string16& search_terms) {
   if (instant_tab_ && instant_tab_->supports_instant() &&
       search_mode_.is_origin_search()) {
     // Use |instant_tab_| to run the query if we're already on a search results
diff --git a/chrome/browser/ui/search/instant_controller.h b/chrome/browser/ui/search/instant_controller.h
index 4f32f06..866ad2c 100644
--- a/chrome/browser/ui/search/instant_controller.h
+++ b/chrome/browser/ui/search/instant_controller.h
@@ -62,7 +62,7 @@ class InstantController : public InstantPage::Delegate {
   // Called if the browser is navigating to a search URL for |search_terms| with
   // search-term-replacement enabled. If |instant_tab_| can be used to process
   // the search, this does so and returns true. Else, returns false.
-  bool SubmitQuery(const string16& search_terms);
+  bool SubmitQuery(const base::string16& search_terms);
 
   // Called to indicate that the omnibox focus state changed with the given
   // |reason|. If |focus_state| is FOCUS_NONE, |view_gaining_focus| is set to
diff --git a/chrome/browser/ui/search/instant_extended_interactive_uitest.cc b/chrome/browser/ui/search/instant_extended_interactive_uitest.cc
index 4d03f33..38aac27 100644
--- a/chrome/browser/ui/search/instant_extended_interactive_uitest.cc
+++ b/chrome/browser/ui/search/instant_extended_interactive_uitest.cc
@@ -229,7 +229,7 @@ class InstantExtendedTest : public InProcessBrowserTest,
     GURL search(template_url->url_ref().ReplaceSearchTerms(
         TemplateURLRef::SearchTermsArgs(term)));
     history->AddPageWithDetails(
-        search, string16(), visit_count, visit_count,
+        search, base::string16(), visit_count, visit_count,
         base::Time::Now(), false, history::SOURCE_BROWSED);
     history->SetKeywordSearchTermsForURL(
         search, template_url->id(), term);
diff --git a/chrome/browser/ui/search/instant_extended_manual_interactive_uitest.cc b/chrome/browser/ui/search/instant_extended_manual_interactive_uitest.cc
index a16e16e..8660b1a 100644
--- a/chrome/browser/ui/search/instant_extended_manual_interactive_uitest.cc
+++ b/chrome/browser/ui/search/instant_extended_manual_interactive_uitest.cc
@@ -166,7 +166,7 @@ IN_PROC_BROWSER_TEST_F(InstantExtendedManualTest, MANUAL_SearchesFromFakebox) {
   EXPECT_EQ(OMNIBOX_FOCUS_VISIBLE, omnibox()->model()->focus_state());
 
   // Pressing enter should search for [test].
-  const string16& search_title = ASCIIToUTF16("test - Google Search");
+  const base::string16& search_title = ASCIIToUTF16("test - Google Search");
   content::TitleWatcher title_watcher(active_tab, search_title);
   PressEnterAndWaitForNavigation();
   EXPECT_EQ(search_title, title_watcher.WaitAndGetTitle());
diff --git a/chrome/browser/ui/search/instant_page.cc b/chrome/browser/ui/search/instant_page.cc
index 5c68682..7e1bec7 100644
--- a/chrome/browser/ui/search/instant_page.cc
+++ b/chrome/browser/ui/search/instant_page.cc
@@ -71,7 +71,7 @@ bool InstantPage::ShouldProcessAboutToNavigateMainFrame() {
 
 void InstantPage::DidCommitProvisionalLoadForFrame(
     int64 /* frame_id */,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& url,
     content::PageTransition /* transition_type */,
@@ -92,11 +92,11 @@ void InstantPage::DidNavigateMainFrame(
 
 void InstantPage::DidFailProvisionalLoad(
     int64 /* frame_id */,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& /* validated_url */,
     int /* error_code */,
-    const string16& /* error_description */,
+    const base::string16& /* error_description */,
     content::RenderViewHost* /* render_view_host */) {
   if (is_main_frame)
     delegate_->InstantPageLoadFailed(contents());
diff --git a/chrome/browser/ui/search/instant_page.h b/chrome/browser/ui/search/instant_page.h
index 6fd20596..8967d91 100644
--- a/chrome/browser/ui/search/instant_page.h
+++ b/chrome/browser/ui/search/instant_page.h
@@ -114,7 +114,7 @@ class InstantPage : public content::WebContentsObserver,
   // Overridden from content::WebContentsObserver:
   virtual void DidCommitProvisionalLoadForFrame(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& url,
       content::PageTransition transition_type,
@@ -124,11 +124,11 @@ class InstantPage : public content::WebContentsObserver,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual void DidFailProvisionalLoad(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& validated_url,
       int error_code,
-      const string16& error_description,
+      const base::string16& error_description,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
   // Overridden from SearchModelObserver:
diff --git a/chrome/browser/ui/search/instant_test_utils.h b/chrome/browser/ui/search/instant_test_utils.h
index 300866a..1e3c7b5 100644
--- a/chrome/browser/ui/search/instant_test_utils.h
+++ b/chrome/browser/ui/search/instant_test_utils.h
@@ -95,7 +95,7 @@ class InstantTestBase {
                  bool* loaded);
 
   // Returns the omnibox's inline autocompletion (shown in blue highlight).
-  string16 GetBlueText();
+  base::string16 GetBlueText();
 
  private:
   GURL instant_url_;
diff --git a/chrome/browser/ui/search/search_ipc_router.cc b/chrome/browser/ui/search/search_ipc_router.cc
index ff1a3f7..e062553 100644
--- a/chrome/browser/ui/search/search_ipc_router.cc
+++ b/chrome/browser/ui/search/search_ipc_router.cc
@@ -25,8 +25,9 @@ void SearchIPCRouter::DetermineIfPageSupportsInstant() {
   Send(new ChromeViewMsg_DetermineIfPageSupportsInstant(routing_id()));
 }
 
-void SearchIPCRouter::SendChromeIdentityCheckResult(const string16& identity,
-                                                    bool identity_match) {
+void SearchIPCRouter::SendChromeIdentityCheckResult(
+    const base::string16& identity,
+    bool identity_match) {
   if (!policy_->ShouldProcessChromeIdentityCheck())
     return;
 
@@ -85,7 +86,7 @@ void SearchIPCRouter::ToggleVoiceSearch() {
   Send(new ChromeViewMsg_SearchBoxToggleVoiceSearch(routing_id()));
 }
 
-void SearchIPCRouter::Submit(const string16& text) {
+void SearchIPCRouter::Submit(const base::string16& text) {
   if (!policy_->ShouldSubmitQuery())
     return;
 
@@ -221,7 +222,7 @@ void SearchIPCRouter::OnLogEvent(int page_id, NTPLoggingEventType event) const {
 }
 
 void SearchIPCRouter::OnPasteAndOpenDropDown(int page_id,
-                                             const string16& text) const {
+                                             const base::string16& text) const {
   if (!web_contents()->IsActiveEntry(page_id))
     return;
 
@@ -232,8 +233,9 @@ void SearchIPCRouter::OnPasteAndOpenDropDown(int page_id,
   delegate_->PasteIntoOmnibox(text);
 }
 
-void SearchIPCRouter::OnChromeIdentityCheck(int page_id,
-                                            const string16& identity) const {
+void SearchIPCRouter::OnChromeIdentityCheck(
+    int page_id,
+    const base::string16& identity) const {
   if (!web_contents()->IsActiveEntry(page_id))
     return;
 
diff --git a/chrome/browser/ui/search/search_ipc_router.h b/chrome/browser/ui/search/search_ipc_router.h
index c2475f30..70c1006 100644
--- a/chrome/browser/ui/search/search_ipc_router.h
+++ b/chrome/browser/ui/search/search_ipc_router.h
@@ -64,12 +64,12 @@ class SearchIPCRouter : public content::WebContentsObserver {
 
     // Called when the page wants to paste the |text| (or the clipboard contents
     // if the |text| is empty) into the omnibox.
-    virtual void PasteIntoOmnibox(const string16& text) = 0;
+    virtual void PasteIntoOmnibox(const base::string16& text) = 0;
 
     // Called when the SearchBox wants to verify the signed-in Chrome identity
     // against the provided |identity|. Will make a round-trip to the browser
     // and eventually return the result through SendChromeIdentityCheckResult.
-    virtual void OnChromeIdentityCheck(const string16& identity) = 0;
+    virtual void OnChromeIdentityCheck(const base::string16& identity) = 0;
   };
 
   // An interface to be implemented by consumers of SearchIPCRouter objects to
@@ -109,7 +109,7 @@ class SearchIPCRouter : public content::WebContentsObserver {
   void DetermineIfPageSupportsInstant();
 
   // Tells the renderer about the result of the Chrome identity check.
-  void SendChromeIdentityCheckResult(const string16& identity,
+  void SendChromeIdentityCheckResult(const base::string16& identity,
                                      bool identity_match);
 
   // Tells the renderer information it needs to display promos.
@@ -131,7 +131,7 @@ class SearchIPCRouter : public content::WebContentsObserver {
   void ToggleVoiceSearch();
 
   // Tells the page that the user pressed Enter in the omnibox.
-  void Submit(const string16& text);
+  void Submit(const base::string16& text);
 
   // Called when the tab corresponding to |this| instance is activated.
   void OnTabActivated();
@@ -169,8 +169,8 @@ class SearchIPCRouter : public content::WebContentsObserver {
   void OnUndoMostVisitedDeletion(int page_id, const GURL& url) const;
   void OnUndoAllMostVisitedDeletions(int page_id) const;
   void OnLogEvent(int page_id, NTPLoggingEventType event) const;
-  void OnPasteAndOpenDropDown(int page_id, const string16& text) const;
-  void OnChromeIdentityCheck(int page_id, const string16& identity) const;
+  void OnPasteAndOpenDropDown(int page_id, const base::string16& text) const;
+  void OnChromeIdentityCheck(int page_id, const base::string16& identity) const;
 
   // Used by unit tests to set a fake delegate.
   void set_delegate(Delegate* delegate);
diff --git a/chrome/browser/ui/search/search_ipc_router_unittest.cc b/chrome/browser/ui/search/search_ipc_router_unittest.cc
index 0e5d6b3..40a4f56 100644
--- a/chrome/browser/ui/search/search_ipc_router_unittest.cc
+++ b/chrome/browser/ui/search/search_ipc_router_unittest.cc
@@ -52,8 +52,8 @@ class MockSearchIPCRouterDelegate : public SearchIPCRouter::Delegate {
   MOCK_METHOD1(OnUndoMostVisitedDeletion, void(const GURL& url));
   MOCK_METHOD0(OnUndoAllMostVisitedDeletions, void());
   MOCK_METHOD1(OnLogEvent, void(NTPLoggingEventType event));
-  MOCK_METHOD1(PasteIntoOmnibox, void(const string16&));
-  MOCK_METHOD1(OnChromeIdentityCheck, void(const string16& identity));
+  MOCK_METHOD1(PasteIntoOmnibox, void(const base::string16&));
+  MOCK_METHOD1(OnChromeIdentityCheck, void(const base::string16& identity));
 };
 
 class MockSearchIPCRouterPolicy : public SearchIPCRouter::Policy {
@@ -355,7 +355,7 @@ TEST_F(SearchIPCRouterTest, ProcessChromeIdentityCheckMsg) {
   NavigateAndCommitActiveTab(GURL(chrome::kChromeSearchLocalNtpUrl));
   SetupMockDelegateAndPolicy();
   MockSearchIPCRouterPolicy* policy = GetSearchIPCRouterPolicy();
-  const string16 test_identity = ASCIIToUTF16("foo@bar.com");
+  const base::string16 test_identity = ASCIIToUTF16("foo@bar.com");
   EXPECT_CALL(*mock_delegate(), OnChromeIdentityCheck(test_identity)).Times(1);
   EXPECT_CALL(*policy, ShouldProcessChromeIdentityCheck()).Times(1)
       .WillOnce(testing::Return(true));
@@ -373,7 +373,7 @@ TEST_F(SearchIPCRouterTest, IgnoreChromeIdentityCheckMsg) {
   SetupMockDelegateAndPolicy();
   MockSearchIPCRouterPolicy* policy = GetSearchIPCRouterPolicy();
 
-  const string16 test_identity = ASCIIToUTF16("foo@bar.com");
+  const base::string16 test_identity = ASCIIToUTF16("foo@bar.com");
   EXPECT_CALL(*mock_delegate(), OnChromeIdentityCheck(test_identity)).Times(0);
   EXPECT_CALL(*policy, ShouldProcessChromeIdentityCheck()).Times(1)
       .WillOnce(testing::Return(false));
@@ -538,7 +538,7 @@ TEST_F(SearchIPCRouterTest, IgnoreMessageIfThePageIsNotActive) {
                                                invalid_page_id, NTP_MOUSEOVER));
   OnMessageReceived(*message);
 
-  string16 text;
+  base::string16 text;
   EXPECT_CALL(*mock_delegate(), PasteIntoOmnibox(text)).Times(0);
   EXPECT_CALL(*policy, ShouldProcessPasteIntoOmnibox(is_active_tab)).Times(0);
   message.reset(new ChromeViewHostMsg_PasteAndOpenDropdown(
@@ -555,7 +555,7 @@ TEST_F(SearchIPCRouterTest, ProcessPasteAndOpenDropdownMsg) {
   bool is_active_tab = IsActiveTab(contents);
   EXPECT_TRUE(is_active_tab);
 
-  string16 text;
+  base::string16 text;
   EXPECT_CALL(*mock_delegate(), PasteIntoOmnibox(text)).Times(1);
   EXPECT_CALL(*policy, ShouldProcessPasteIntoOmnibox(is_active_tab)).Times(1)
       .WillOnce(testing::Return(true));
@@ -568,7 +568,7 @@ TEST_F(SearchIPCRouterTest, ProcessPasteAndOpenDropdownMsg) {
 TEST_F(SearchIPCRouterTest, IgnorePasteAndOpenDropdownMsg) {
   NavigateAndCommitActiveTab(GURL("chrome-search://foo/bar"));
   SetupMockDelegateAndPolicy();
-  string16 text;
+  base::string16 text;
   EXPECT_CALL(*mock_delegate(), PasteIntoOmnibox(text)).Times(0);
 
   content::WebContents* contents = web_contents();
diff --git a/chrome/browser/ui/search/search_tab_helper.cc b/chrome/browser/ui/search/search_tab_helper.cc
index 9218277..f779ede 100644
--- a/chrome/browser/ui/search/search_tab_helper.cc
+++ b/chrome/browser/ui/search/search_tab_helper.cc
@@ -199,7 +199,7 @@ void SearchTabHelper::SetSuggestionToPrefetch(
   ipc_router_.SetSuggestionToPrefetch(suggestion);
 }
 
-void SearchTabHelper::Submit(const string16& text) {
+void SearchTabHelper::Submit(const base::string16& text) {
   ipc_router_.Submit(text);
 }
 
@@ -270,11 +270,11 @@ void SearchTabHelper::DidNavigateMainFrame(
 
 void SearchTabHelper::DidFailProvisionalLoad(
     int64 /* frame_id */,
-    const string16& /* frame_unique_name */,
+    const base::string16& /* frame_unique_name */,
     bool is_main_frame,
     const GURL& validated_url,
     int /* error_code */,
-    const string16& /* error_description */,
+    const base::string16& /* error_description */,
     content::RenderViewHost* /* render_view_host */) {
   if (is_main_frame &&
       chrome::ShouldUseCacheableNTP() &&
@@ -491,7 +491,7 @@ void SearchTabHelper::OnLogEvent(NTPLoggingEventType event) {
     data->LogEvent(event);
 }
 
-void SearchTabHelper::PasteIntoOmnibox(const string16& text) {
+void SearchTabHelper::PasteIntoOmnibox(const base::string16& text) {
 // iOS and Android don't use the Instant framework.
 #if !defined(OS_IOS) && !defined(OS_ANDROID)
   Browser* browser = chrome::FindBrowserWithWebContents(web_contents());
@@ -503,7 +503,7 @@ void SearchTabHelper::PasteIntoOmnibox(const string16& text) {
   // from the clipboard already sanitized. The second case is needed to handle
   // drag-and-drop value and it has to be sanitazed before setting it into the
   // omnibox.
-  string16 text_to_paste = text.empty() ? omnibox->GetClipboardText() :
+  base::string16 text_to_paste = text.empty() ? omnibox->GetClipboardText() :
       omnibox->SanitizeTextForPaste(text);
 
   if (text_to_paste.empty())
@@ -519,10 +519,11 @@ void SearchTabHelper::PasteIntoOmnibox(const string16& text) {
 #endif
 }
 
-void SearchTabHelper::OnChromeIdentityCheck(const string16& identity) {
+void SearchTabHelper::OnChromeIdentityCheck(const base::string16& identity) {
   SigninManagerBase* manager = SigninManagerFactory::GetForProfile(profile());
   if (manager) {
-    const string16 username = UTF8ToUTF16(manager->GetAuthenticatedUsername());
+    const base::string16 username =
+        UTF8ToUTF16(manager->GetAuthenticatedUsername());
     ipc_router_.SendChromeIdentityCheckResult(identity,
                                               identity == username);
   }
diff --git a/chrome/browser/ui/search/search_tab_helper.h b/chrome/browser/ui/search/search_tab_helper.h
index 7c62944..e6f28b9 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -72,7 +72,7 @@ class SearchTabHelper : public content::WebContentsObserver,
   void SetSuggestionToPrefetch(const InstantSuggestion& suggestion);
 
   // Tells the page that the user pressed Enter in the omnibox.
-  void Submit(const string16& text);
+  void Submit(const base::string16& text);
 
   // Called when the tab corresponding to |this| instance is activated.
   void OnTabActivated();
@@ -135,11 +135,11 @@ class SearchTabHelper : public content::WebContentsObserver,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual void DidFailProvisionalLoad(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& validated_url,
       int error_code,
-      const string16& error_description,
+      const base::string16& error_description,
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void DidFinishLoad(
       int64 frame_id,
@@ -160,8 +160,8 @@ class SearchTabHelper : public content::WebContentsObserver,
   virtual void OnUndoMostVisitedDeletion(const GURL& url) OVERRIDE;
   virtual void OnUndoAllMostVisitedDeletions() OVERRIDE;
   virtual void OnLogEvent(NTPLoggingEventType event) OVERRIDE;
-  virtual void PasteIntoOmnibox(const string16& text) OVERRIDE;
-  virtual void OnChromeIdentityCheck(const string16& identity) OVERRIDE;
+  virtual void PasteIntoOmnibox(const base::string16& text) OVERRIDE;
+  virtual void OnChromeIdentityCheck(const base::string16& identity) OVERRIDE;
 
   // Overridden from InstantServiceObserver:
   virtual void ThemeInfoChanged(const ThemeBackgroundInfo& theme_info) OVERRIDE;
diff --git a/chrome/browser/ui/search/search_tab_helper_unittest.cc b/chrome/browser/ui/search/search_tab_helper_unittest.cc
index 33d51dd..923983b 100644
--- a/chrome/browser/ui/search/search_tab_helper_unittest.cc
+++ b/chrome/browser/ui/search/search_tab_helper_unittest.cc
@@ -49,8 +49,8 @@ class MockSearchIPCRouterDelegate : public SearchIPCRouter::Delegate {
   MOCK_METHOD1(OnUndoMostVisitedDeletion, void(const GURL& url));
   MOCK_METHOD0(OnUndoAllMostVisitedDeletions, void());
   MOCK_METHOD1(OnLogEvent, void(NTPLoggingEventType event));
-  MOCK_METHOD1(PasteIntoOmnibox, void(const string16&));
-  MOCK_METHOD1(OnChromeIdentityCheck, void(const string16& identity));
+  MOCK_METHOD1(PasteIntoOmnibox, void(const base::string16&));
+  MOCK_METHOD1(OnChromeIdentityCheck, void(const base::string16& identity));
 };
 
 }  // namespace
@@ -141,7 +141,7 @@ TEST_F(SearchTabHelperTest, OnChromeIdentityCheckMatch) {
       SearchTabHelper::FromWebContents(web_contents());
   ASSERT_NE(static_cast<SearchTabHelper*>(NULL), search_tab_helper);
 
-  const string16 test_identity = ASCIIToUTF16("foo@bar.com");
+  const base::string16 test_identity = ASCIIToUTF16("foo@bar.com");
   search_tab_helper->OnChromeIdentityCheck(test_identity);
 
   const IPC::Message* message = process()->sink().GetUniqueMessageMatching(
@@ -161,7 +161,7 @@ TEST_F(SearchTabHelperTest, OnChromeIdentityCheckMismatch) {
       SearchTabHelper::FromWebContents(web_contents());
   ASSERT_NE(static_cast<SearchTabHelper*>(NULL), search_tab_helper);
 
-  const string16 test_identity = ASCIIToUTF16("bar@foo.com");
+  const base::string16 test_identity = ASCIIToUTF16("bar@foo.com");
   search_tab_helper->OnChromeIdentityCheck(test_identity);
 
   const IPC::Message* message = process()->sink().GetUniqueMessageMatching(
@@ -181,7 +181,7 @@ TEST_F(SearchTabHelperTest, OnChromeIdentityCheckSignedOutMatch) {
       SearchTabHelper::FromWebContents(web_contents());
   ASSERT_NE(static_cast<SearchTabHelper*>(NULL), search_tab_helper);
 
-  const string16 test_identity;
+  const base::string16 test_identity;
   search_tab_helper->OnChromeIdentityCheck(test_identity);
 
   const IPC::Message* message = process()->sink().GetUniqueMessageMatching(
@@ -201,7 +201,7 @@ TEST_F(SearchTabHelperTest, OnChromeIdentityCheckSignedOutMismatch) {
       SearchTabHelper::FromWebContents(web_contents());
   ASSERT_NE(static_cast<SearchTabHelper*>(NULL), search_tab_helper);
 
-  const string16 test_identity = ASCIIToUTF16("bar@foo.com");
+  const base::string16 test_identity = ASCIIToUTF16("bar@foo.com");
   search_tab_helper->OnChromeIdentityCheck(test_identity);
 
   const IPC::Message* message = process()->sink().GetUniqueMessageMatching(
@@ -219,8 +219,8 @@ class TabTitleObserver : public content::WebContentsObserver {
   explicit TabTitleObserver(content::WebContents* contents)
       : WebContentsObserver(contents) {}
 
-  string16 title_on_start() { return title_on_start_; }
-  string16 title_on_commit() { return title_on_commit_; }
+  base::string16 title_on_start() { return title_on_start_; }
+  base::string16 title_on_commit() { return title_on_commit_; }
 
  private:
   virtual void DidStartProvisionalLoadForFrame(
@@ -240,14 +240,14 @@ class TabTitleObserver : public content::WebContentsObserver {
     title_on_commit_ = web_contents()->GetTitle();
   }
 
-  string16 title_on_start_;
-  string16 title_on_commit_;
+  base::string16 title_on_start_;
+  base::string16 title_on_commit_;
 };
 
 TEST_F(SearchTabHelperTest, TitleIsSetForNTP) {
   TabTitleObserver title_observer(web_contents());
   NavigateAndCommit(GURL(chrome::kChromeUINewTabURL));
-  const string16 title = l10n_util::GetStringUTF16(IDS_NEW_TAB_TITLE);
+  const base::string16 title = l10n_util::GetStringUTF16(IDS_NEW_TAB_TITLE);
   EXPECT_EQ(title, title_observer.title_on_start());
   EXPECT_EQ(title, title_observer.title_on_commit());
   EXPECT_EQ(title, web_contents()->GetTitle());
diff --git a/chrome/browser/ui/status_bubble.h b/chrome/browser/ui/status_bubble.h
index fad678a..aee0a79 100644
--- a/chrome/browser/ui/status_bubble.h
+++ b/chrome/browser/ui/status_bubble.h
@@ -31,7 +31,7 @@ class StatusBubble {
   // when the cursor exits a link) will set the status bubble back to its
   // status text. To hide the status bubble again, either call SetStatus
   // with an empty string, or call Hide().
-  virtual void SetStatus(const string16& status) = 0;
+  virtual void SetStatus(const base::string16& status) = 0;
 
   // Sets the bubble text to a URL - if given a non-empty URL, this will cause
   // the bubble to fade in and remain open until given an empty URL or until
diff --git a/chrome/browser/ui/sync/inline_login_dialog.cc b/chrome/browser/ui/sync/inline_login_dialog.cc
index 8444a35..4ef93e8 100644
--- a/chrome/browser/ui/sync/inline_login_dialog.cc
+++ b/chrome/browser/ui/sync/inline_login_dialog.cc
@@ -24,7 +24,7 @@ ui::ModalType InlineLoginDialog::GetDialogModalType() const {
 }
 
 string16 InlineLoginDialog::GetDialogTitle() const {
-  return string16();
+  return base::string16();
 }
 
 GURL InlineLoginDialog::GetDialogContentURL() const {
diff --git a/chrome/browser/ui/sync/inline_login_dialog.h b/chrome/browser/ui/sync/inline_login_dialog.h
index 076fca5..00fcd6c 100644
--- a/chrome/browser/ui/sync/inline_login_dialog.h
+++ b/chrome/browser/ui/sync/inline_login_dialog.h
@@ -26,7 +26,7 @@ class InlineLoginDialog : public ui::WebDialogDelegate {
 
   // ui::WebDialogDelegate overrides:
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
-  virtual string16 GetDialogTitle() const OVERRIDE;
+  virtual base::string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<content::WebUIMessageHandler*>* handlers) const OVERRIDE;
diff --git a/chrome/browser/ui/sync/one_click_signin_helper.cc b/chrome/browser/ui/sync/one_click_signin_helper.cc
index 8abeb75..9150170 100644
--- a/chrome/browser/ui/sync/one_click_signin_helper.cc
+++ b/chrome/browser/ui/sync/one_click_signin_helper.cc
@@ -175,11 +175,11 @@ class ConfirmEmailDialogDelegate : public TabModalConfirmDialogDelegate {
   virtual ~ConfirmEmailDialogDelegate();
 
   // TabModalConfirmDialogDelegate:
-  virtual string16 GetTitle() OVERRIDE;
-  virtual string16 GetMessage() OVERRIDE;
-  virtual string16 GetAcceptButtonTitle() OVERRIDE;
-  virtual string16 GetCancelButtonTitle() OVERRIDE;
-  virtual string16 GetLinkText() const OVERRIDE;
+  virtual base::string16 GetTitle() OVERRIDE;
+  virtual base::string16 GetMessage() OVERRIDE;
+  virtual base::string16 GetAcceptButtonTitle() OVERRIDE;
+  virtual base::string16 GetCancelButtonTitle() OVERRIDE;
+  virtual base::string16 GetLinkText() const OVERRIDE;
   virtual void OnAccepted() OVERRIDE;
   virtual void OnCanceled() OVERRIDE;
   virtual void OnClosed() OVERRIDE;
@@ -543,7 +543,7 @@ class CurrentHistoryCleaner : public content::WebContentsObserver {
   virtual void WebContentsDestroyed(content::WebContents* contents) OVERRIDE;
   virtual void DidCommitProvisionalLoadForFrame(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& url,
       content::PageTransition transition_type,
@@ -567,7 +567,7 @@ CurrentHistoryCleaner::~CurrentHistoryCleaner() {
 
 void CurrentHistoryCleaner::DidCommitProvisionalLoadForFrame(
     int64 frame_id,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& url,
     content::PageTransition transition_type,
@@ -728,7 +728,7 @@ bool OneClickSigninHelper::CanOffer(content::WebContents* web_contents,
       if (g_browser_process && !same_email) {
         ProfileManager* manager = g_browser_process->profile_manager();
         if (manager) {
-          string16 email16 = UTF8ToUTF16(email);
+          base::string16 email16 = UTF8ToUTF16(email);
           ProfileInfoCache& cache = manager->GetProfileInfoCache();
 
           for (size_t i = 0; i < cache.GetNumberOfProfiles(); ++i) {
@@ -1028,7 +1028,7 @@ void OneClickSigninHelper::ShowSigninErrorBubble(Browser* browser,
 
   browser->window()->ShowOneClickSigninBubble(
       BrowserWindow::ONE_CLICK_SIGNIN_BUBBLE_TYPE_BUBBLE,
-      string16(), /* no SAML email */
+      base::string16(), /* no SAML email */
       UTF8ToUTF16(error),
       // This callback is never invoked.
       // TODO(rogerta): Separate out the bubble API so we don't have to pass
diff --git a/chrome/browser/ui/sync/one_click_signin_sync_starter.cc b/chrome/browser/ui/sync/one_click_signin_sync_starter.cc
index 86ee6de..e075f48 100644
--- a/chrome/browser/ui/sync/one_click_signin_sync_starter.cc
+++ b/chrome/browser/ui/sync/one_click_signin_sync_starter.cc
@@ -318,7 +318,7 @@ void OneClickSigninSyncStarter::ConfirmAndSignin() {
     browser_->window()->ShowOneClickSigninBubble(
         BrowserWindow::ONE_CLICK_SIGNIN_BUBBLE_TYPE_SAML_MODAL_DIALOG,
         UTF8ToUTF16(signin->GetUsernameForAuthInProgress()),
-        string16(), // No error message to display.
+        base::string16(), // No error message to display.
         base::Bind(&OneClickSigninSyncStarter::UntrustedSigninConfirmed,
                    weak_pointer_factory_.GetWeakPtr()));
   } else {
@@ -377,7 +377,7 @@ void OneClickSigninSyncStarter::SigninSuccess() {
         profile_sync_service->SetSyncSetupCompleted();
       FinishProfileSyncServiceSetup();
       if (confirmation_required_ == CONFIRM_AFTER_SIGNIN) {
-        string16 message;
+        base::string16 message;
         if (!profile_sync_service) {
           // Sync is disabled by policy.
           message = l10n_util::GetStringUTF16(
@@ -400,11 +400,11 @@ void OneClickSigninSyncStarter::SigninSuccess() {
 }
 
 void OneClickSigninSyncStarter::DisplayFinalConfirmationBubble(
-    const string16& custom_message) {
+    const base::string16& custom_message) {
   EnsureBrowser();
   browser_->window()->ShowOneClickSigninBubble(
       BrowserWindow::ONE_CLICK_SIGNIN_BUBBLE_TYPE_BUBBLE,
-      string16(),  // No email required - this is not a SAML confirmation.
+      base::string16(),  // No email required - this is not a SAML confirmation.
       custom_message,
       // Callback is ignored.
       BrowserWindow::StartSyncCallback());
diff --git a/chrome/browser/ui/sync/one_click_signin_sync_starter.h b/chrome/browser/ui/sync/one_click_signin_sync_starter.h
index c8087ce..e70c754 100644
--- a/chrome/browser/ui/sync/one_click_signin_sync_starter.h
+++ b/chrome/browser/ui/sync/one_click_signin_sync_starter.h
@@ -192,7 +192,7 @@ class OneClickSigninSyncStarter : public SigninTracker::Observer,
 
   // Shows the post-signin confirmation bubble. If |custom_message| is empty,
   // the default "You are signed in" message is displayed.
-  void DisplayFinalConfirmationBubble(const string16& custom_message);
+  void DisplayFinalConfirmationBubble(const base::string16& custom_message);
 
   // Makes sure browser_ points to a valid browser (opens a new browser if
   // necessary). Useful in the case where the user has created a new Profile as
diff --git a/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc b/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
index 84e9aa6..47ce5cf 100644
--- a/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
+++ b/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
@@ -143,7 +143,7 @@ void ProfileSigninConfirmationHelper::CheckHasHistory(int max_entries) {
   history::QueryOptions opts;
   opts.max_count = max_entries;
   service->QueryHistory(
-      string16(), opts, &request_consumer_,
+      base::string16(), opts, &request_consumer_,
       base::Bind(&ProfileSigninConfirmationHelper::OnHistoryQueryResults,
                  this,
                  max_entries));
diff --git a/chrome/browser/ui/sync/profile_signin_confirmation_helper_unittest.cc b/chrome/browser/ui/sync/profile_signin_confirmation_helper_unittest.cc
index 8dc335c..58cb52a 100644
--- a/chrome/browser/ui/sync/profile_signin_confirmation_helper_unittest.cc
+++ b/chrome/browser/ui/sync/profile_signin_confirmation_helper_unittest.cc
@@ -181,8 +181,8 @@ TEST_F(ProfileSigninConfirmationHelperTest, PromptForNewProfile_Bookmarks) {
   ASSERT_TRUE(model_);
 
   // Profile is new but has bookmarks.
-  model_->AddURL(model_->bookmark_bar_node(), 0, string16(ASCIIToUTF16("foo")),
-                 GURL("http://foo.com"));
+  model_->AddURL(model_->bookmark_bar_node(), 0,
+                 base::string16(ASCIIToUTF16("foo")), GURL("http://foo.com"));
   EXPECT_TRUE(
       GetCallbackResult(
           base::Bind(
diff --git a/chrome/browser/ui/tab_modal_confirm_dialog_delegate.cc b/chrome/browser/ui/tab_modal_confirm_dialog_delegate.cc
index ad3884d..fb2d922 100644
--- a/chrome/browser/ui/tab_modal_confirm_dialog_delegate.cc
+++ b/chrome/browser/ui/tab_modal_confirm_dialog_delegate.cc
@@ -89,7 +89,7 @@ string16 TabModalConfirmDialogDelegate::GetCancelButtonTitle() {
 }
 
 string16 TabModalConfirmDialogDelegate::GetLinkText() const {
-  return string16();
+  return base::string16();
 }
 
 const char* TabModalConfirmDialogDelegate::GetAcceptButtonIcon() {
diff --git a/chrome/browser/ui/tab_modal_confirm_dialog_delegate.h b/chrome/browser/ui/tab_modal_confirm_dialog_delegate.h
index f872ee3..2aa2130 100644
--- a/chrome/browser/ui/tab_modal_confirm_dialog_delegate.h
+++ b/chrome/browser/ui/tab_modal_confirm_dialog_delegate.h
@@ -70,8 +70,8 @@ class TabModalConfirmDialogDelegate : public content::NotificationObserver {
   void LinkClicked(WindowOpenDisposition disposition);
 
   // The title of the dialog. Note that the title is not shown on all platforms.
-  virtual string16 GetTitle() = 0;
-  virtual string16 GetMessage() = 0;
+  virtual base::string16 GetTitle() = 0;
+  virtual base::string16 GetMessage() = 0;
 
   // Icon to show for the dialog. If this method is not overridden, a default
   // icon (like the application icon) is shown.
@@ -79,12 +79,12 @@ class TabModalConfirmDialogDelegate : public content::NotificationObserver {
 
   // Title for the accept and the cancel buttons.
   // The default implementation uses IDS_OK and IDS_CANCEL.
-  virtual string16 GetAcceptButtonTitle();
-  virtual string16 GetCancelButtonTitle();
+  virtual base::string16 GetAcceptButtonTitle();
+  virtual base::string16 GetCancelButtonTitle();
 
   // Returns the text of the link to be displayed, if any. Otherwise returns
   // an empty string.
-  virtual string16 GetLinkText() const;
+  virtual base::string16 GetLinkText() const;
 
   // GTK stock icon names for the accept and cancel buttons, respectively.
   // The icons are only used on GTK. If these methods are not overriden,
diff --git a/chrome/browser/ui/test/test_confirm_bubble_model.h b/chrome/browser/ui/test/test_confirm_bubble_model.h
index 5a09f6a5..7be7725 100644
--- a/chrome/browser/ui/test/test_confirm_bubble_model.h
+++ b/chrome/browser/ui/test/test_confirm_bubble_model.h
@@ -19,14 +19,14 @@ class TestConfirmBubbleModel : public ConfirmBubbleModel {
   virtual ~TestConfirmBubbleModel();
 
   // ConfirmBubbleModel overrides:
-  virtual string16 GetTitle() const OVERRIDE;
-  virtual string16 GetMessageText() const OVERRIDE;
+  virtual base::string16 GetTitle() const OVERRIDE;
+  virtual base::string16 GetMessageText() const OVERRIDE;
   virtual gfx::Image* GetIcon() const OVERRIDE;
   virtual int GetButtons() const OVERRIDE;
-  virtual string16 GetButtonLabel(BubbleButton button) const OVERRIDE;
+  virtual base::string16 GetButtonLabel(BubbleButton button) const OVERRIDE;
   virtual void Accept() OVERRIDE;
   virtual void Cancel() OVERRIDE;
-  virtual string16 GetLinkText() const OVERRIDE;
+  virtual base::string16 GetLinkText() const OVERRIDE;
   virtual void LinkClicked() OVERRIDE;
 
  private:
diff --git a/chrome/browser/ui/views/apps/native_app_window_views.cc b/chrome/browser/ui/views/apps/native_app_window_views.cc
index c5a8b95..886f7b9 100644
--- a/chrome/browser/ui/views/apps/native_app_window_views.cc
+++ b/chrome/browser/ui/views/apps/native_app_window_views.cc
@@ -299,7 +299,7 @@ void NativeAppWindowViews::InitializeDefaultWindow(
   }
 
 #if defined(OS_WIN)
-  string16 app_name_wide = UTF8ToWide(app_name);
+  base::string16 app_name_wide = UTF8ToWide(app_name);
   HWND hwnd = GetNativeAppWindowHWND();
   ui::win::SetAppIdForWindow(ShellIntegration::GetAppModelIdForProfile(
       app_name_wide, profile()->GetPath()), hwnd);
diff --git a/chrome/browser/ui/views/apps/native_app_window_views.h b/chrome/browser/ui/views/apps/native_app_window_views.h
index 10b69c6..4c4338b 100644
--- a/chrome/browser/ui/views/apps/native_app_window_views.h
+++ b/chrome/browser/ui/views/apps/native_app_window_views.h
@@ -127,7 +127,7 @@ class NativeAppWindowViews : public apps::NativeAppWindow,
   virtual views::View* GetInitiallyFocusedView() OVERRIDE;
   virtual bool CanResize() const OVERRIDE;
   virtual bool CanMaximize() const OVERRIDE;
-  virtual string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
   virtual bool ShouldShowWindowTitle() const OVERRIDE;
   virtual gfx::ImageSkia GetWindowAppIcon() OVERRIDE;
   virtual gfx::ImageSkia GetWindowIcon() OVERRIDE;
diff --git a/chrome/browser/ui/views/external_tab_container_win.cc b/chrome/browser/ui/views/external_tab_container_win.cc
index aae3926..a16b79f 100644
--- a/chrome/browser/ui/views/external_tab_container_win.cc
+++ b/chrome/browser/ui/views/external_tab_container_win.cc
@@ -753,11 +753,12 @@ void ExternalTabContainerWin::AddNewContents(WebContents* source,
   }
 }
 
-void ExternalTabContainerWin::WebContentsCreated(WebContents* source_contents,
-                                                 int64 source_frame_id,
-                                                 const string16& frame_name,
-                                                 const GURL& target_url,
-                                                 WebContents* new_contents) {
+void ExternalTabContainerWin::WebContentsCreated(
+    WebContents* source_contents,
+    int64 source_frame_id,
+    const base::string16& frame_name,
+    const GURL& target_url,
+    WebContents* new_contents) {
   if (!load_requests_via_automation_)
     return;
 
@@ -802,7 +803,7 @@ void ExternalTabContainerWin::UpdateTargetURL(WebContents* source,
                                               int32 page_id,
                                               const GURL& url) {
   if (automation_) {
-    string16 url_string = base::UTF8ToUTF16(url.spec());
+    base::string16 url_string = base::UTF8ToUTF16(url.spec());
     automation_->Send(
         new AutomationMsg_UpdateTargetUrl(tab_handle_, url_string));
   }
@@ -1021,7 +1022,7 @@ void ExternalTabContainerWin::RegisterProtocolHandler(
     WebContents* tab,
     const std::string& protocol,
     const GURL& url,
-    const string16& title,
+    const base::string16& title,
     bool user_gesture) {
   Browser::RegisterProtocolHandlerHelper(tab, protocol, url, title,
                                          user_gesture, NULL);
@@ -1071,11 +1072,11 @@ bool ExternalTabContainerWin::OnMessageReceived(const IPC::Message& message) {
 
 void ExternalTabContainerWin::DidFailProvisionalLoad(
     int64 frame_id,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& validated_url,
     int error_code,
-    const string16& error_description,
+    const base::string16& error_description,
     content::RenderViewHost* render_view_host) {
   if (automation_) {
     automation_->Send(new AutomationMsg_NavigationFailed(
diff --git a/chrome/browser/ui/views/first_run_bubble.cc b/chrome/browser/ui/views/first_run_bubble.cc
index 7b74f2e..030e7bb 100644
--- a/chrome/browser/ui/views/first_run_bubble.cc
+++ b/chrome/browser/ui/views/first_run_bubble.cc
@@ -42,7 +42,7 @@ void FirstRunBubble::Init() {
 
   views::Label* title = new views::Label(l10n_util::GetStringFUTF16(
       IDS_FR_BUBBLE_TITLE, browser_ ?
-          GetDefaultSearchEngineName(browser_->profile()) : string16()));
+          GetDefaultSearchEngineName(browser_->profile()) : base::string16()));
   title->SetFont(original_font.DeriveFont(2, gfx::Font::BOLD));
 
   views::Link* change =
diff --git a/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc b/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
index 11bdb83..bbc3345 100644
--- a/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
+++ b/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
@@ -87,7 +87,7 @@ void BrowserNonClientFrameView::UpdateAvatarInfo() {
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   gfx::Image avatar;
   gfx::Image taskbar_badge_avatar;
-  string16 text;
+  base::string16 text;
   bool is_rectangle = false;
   if (browser_view_->IsGuestSession()) {
     avatar = rb.GetImageNamed(browser_view_->GetGuestIconResourceID());
@@ -148,7 +148,7 @@ void BrowserNonClientFrameView::UpdateNewStyleAvatarInfo(
 
   if (browser_view_->ShouldShowAvatar()) {
     if (!new_avatar_button_) {
-      string16 profile_name =
+      base::string16 profile_name =
           profiles::GetActiveProfileDisplayName(browser_view_->browser());
       new_avatar_button_ = new NewAvatarButton(
           listener, profile_name, style, browser_view_->browser());
diff --git a/chrome/browser/ui/views/frame/browser_root_view.cc b/chrome/browser/ui/views/frame/browser_root_view.cc
index 3ebb52b..06ded06 100644
--- a/chrome/browser/ui/views/frame/browser_root_view.cc
+++ b/chrome/browser/ui/views/frame/browser_root_view.cc
@@ -94,17 +94,17 @@ int BrowserRootView::OnPerformDrop(const ui::DropTargetEvent& event) {
   // do this as the TabStrip doesn't know about the autocomplete edit and needs
   // to know about it to handle 'paste and go'.
   GURL url;
-  string16 title;
+  base::string16 title;
   ui::OSExchangeData mapped_data;
   if (!event.data().GetURLAndTitle(&url, &title) || !url.is_valid()) {
     // The url isn't valid. Use the paste and go url.
     if (GetPasteAndGoURL(event.data(), &url))
-      mapped_data.SetURL(url, string16());
+      mapped_data.SetURL(url, base::string16());
     // else case: couldn't extract a url or 'paste and go' url. This ends up
     // passing through an ui::OSExchangeData with nothing in it. We need to do
     // this so that the tab strip cleans up properly.
   } else {
-    mapped_data.SetURL(url, string16());
+    mapped_data.SetURL(url, base::string16());
   }
   forwarding_to_tab_strip_ = false;
   scoped_ptr<ui::DropTargetEvent> mapped_event(
@@ -185,7 +185,7 @@ bool BrowserRootView::GetPasteAndGoURL(const ui::OSExchangeData& data,
   if (!data.HasString())
     return false;
 
-  string16 text;
+  base::string16 text;
   if (!data.GetString(&text) || text.empty())
     return false;
   text = AutocompleteMatch::SanitizeString(text);
diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index 6149121..ed77b66 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -1215,8 +1215,8 @@ void BrowserView::ShowTranslateBubble(
 #if defined(ENABLE_ONE_CLICK_SIGNIN)
 void BrowserView::ShowOneClickSigninBubble(
     OneClickSigninBubbleType type,
-    const string16& email,
-    const string16& error_message,
+    const base::string16& email,
+    const base::string16& error_message,
     const StartSyncCallback& start_sync_callback) {
   scoped_ptr<OneClickSigninBubbleDelegate> delegate;
   delegate.reset(new OneClickSigninBubbleLinksDelegate(browser()));
diff --git a/chrome/browser/ui/views/frame/browser_view.h b/chrome/browser/ui/views/frame/browser_view.h
index a053d2c..d53f373 100644
--- a/chrome/browser/ui/views/frame/browser_view.h
+++ b/chrome/browser/ui/views/frame/browser_view.h
@@ -333,8 +333,8 @@ class BrowserView : public BrowserWindow,
 #if defined(ENABLE_ONE_CLICK_SIGNIN)
   virtual void ShowOneClickSigninBubble(
       OneClickSigninBubbleType type,
-      const string16& email,
-      const string16& error_message,
+      const base::string16& email,
+      const base::string16& error_message,
       const StartSyncCallback& start_sync_callback) OVERRIDE;
 #endif
   // TODO(beng): Not an override, move somewhere else.
@@ -397,8 +397,8 @@ class BrowserView : public BrowserWindow,
   virtual bool CanResize() const OVERRIDE;
   virtual bool CanMaximize() const OVERRIDE;
   virtual bool CanActivate() const OVERRIDE;
-  virtual string16 GetWindowTitle() const OVERRIDE;
-  virtual string16 GetAccessibleWindowTitle() const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetAccessibleWindowTitle() const OVERRIDE;
   virtual views::View* GetInitiallyFocusedView() OVERRIDE;
   virtual bool ShouldShowWindowTitle() const OVERRIDE;
   virtual gfx::ImageSkia GetWindowAppIcon() OVERRIDE;
diff --git a/chrome/browser/ui/views/frame/browser_view_unittest.cc b/chrome/browser/ui/views/frame/browser_view_unittest.cc
index fb3bc91..ee53aaa 100644
--- a/chrome/browser/ui/views/frame/browser_view_unittest.cc
+++ b/chrome/browser/ui/views/frame/browser_view_unittest.cc
@@ -120,7 +120,7 @@ TEST_F(BrowserViewTest, BrowserViewLayout) {
   // Bookmark bar is reparented to BrowserView on NTP.
   NavigateAndCommitActiveTabWithTitle(browser,
                                       GURL(chrome::kChromeUINewTabURL),
-                                      string16());
+                                      base::string16());
   EXPECT_TRUE(bookmark_bar->visible());
   EXPECT_TRUE(bookmark_bar->IsDetached());
   EXPECT_EQ(browser_view(), bookmark_bar->parent());
@@ -148,7 +148,7 @@ TEST_F(BrowserViewTest, BrowserViewLayout) {
   // Bookmark bar is parented back to top container on normal page.
   NavigateAndCommitActiveTabWithTitle(browser,
                                       GURL("about:blank"),
-                                      string16());
+                                      base::string16());
   EXPECT_FALSE(bookmark_bar->visible());
   EXPECT_FALSE(bookmark_bar->IsDetached());
   EXPECT_EQ(top_container, bookmark_bar->parent());
diff --git a/chrome/browser/ui/views/frame/browser_window_property_manager_win.cc b/chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
index 7ce3bef..87cee29 100644
--- a/chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
+++ b/chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
@@ -42,13 +42,13 @@ void BrowserWindowPropertyManager::UpdateWindowProperties(HWND hwnd) {
 
   // Set the app user model id for this application to that of the application
   // name. See http://crbug.com/7028.
-  string16 app_id = browser->is_app() ?
+  base::string16 app_id = browser->is_app() ?
       ShellIntegration::GetAppModelIdForProfile(UTF8ToWide(browser->app_name()),
                                                 profile->GetPath()) :
       ShellIntegration::GetChromiumModelIdForProfile(profile->GetPath());
-  string16 icon_path_string;
-  string16 command_line_string;
-  string16 pinned_name;
+  base::string16 icon_path_string;
+  base::string16 command_line_string;
+  base::string16 pinned_name;
   ProfileManager* profile_manager = g_browser_process->profile_manager();
   ProfileShortcutManager* shortcut_manager = NULL;
 
diff --git a/chrome/browser/ui/views/frame/global_menu_bar_x11.cc b/chrome/browser/ui/views/frame/global_menu_bar_x11.cc
index fcecb76..5b91665 100644
--- a/chrome/browser/ui/views/frame/global_menu_bar_x11.cc
+++ b/chrome/browser/ui/views/frame/global_menu_bar_x11.cc
@@ -290,7 +290,7 @@ struct GlobalMenuBarX11::HistoryItem {
   HistoryItem() : session_id(0) {}
 
   // The title for the menu item.
-  string16 title;
+  base::string16 title;
   // The URL that will be navigated to if the user selects this item.
   GURL url;
 
@@ -525,7 +525,7 @@ void GlobalMenuBarX11::AddHistoryItemToMenu(HistoryItem* item,
                                             DbusmenuMenuitem* menu,
                                             int tag,
                                             int index) {
-  string16 title = item->title;
+  base::string16 title = item->title;
   std::string url_string = item->url.possibly_invalid_spec();
 
   if (title.empty())
diff --git a/chrome/browser/ui/views/frame/opaque_browser_frame_view.h b/chrome/browser/ui/views/frame/opaque_browser_frame_view.h
index 34ecde5..667d844 100644
--- a/chrome/browser/ui/views/frame/opaque_browser_frame_view.h
+++ b/chrome/browser/ui/views/frame/opaque_browser_frame_view.h
@@ -76,7 +76,7 @@ class OpaqueBrowserFrameView : public BrowserNonClientFrameView,
   // OpaqueBrowserFrameViewLayoutDelegate implementation:
   virtual bool ShouldShowWindowIcon() const OVERRIDE;
   virtual bool ShouldShowWindowTitle() const OVERRIDE;
-  virtual string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
   virtual int GetIconSize() const OVERRIDE;
   virtual bool ShouldLeaveOffsetNearTopBorder() const OVERRIDE;
   virtual gfx::Size GetBrowserViewMinimumSize() const OVERRIDE;
diff --git a/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_delegate.h b/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_delegate.h
index a0be77a..7c0e61a 100644
--- a/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_delegate.h
+++ b/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_delegate.h
@@ -17,7 +17,7 @@ class OpaqueBrowserFrameViewLayoutDelegate {
   // mode.
   virtual bool ShouldShowWindowIcon() const = 0;
   virtual bool ShouldShowWindowTitle() const = 0;
-  virtual string16 GetWindowTitle() const = 0;
+  virtual base::string16 GetWindowTitle() const = 0;
 
   // Returns the size of the window icon. This can be platform dependent
   // because of differences in fonts, so its part of the interface.
diff --git a/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_unittest.cc b/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_unittest.cc
index 6c841700..c4ebbc7 100644
--- a/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_unittest.cc
+++ b/chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_unittest.cc
@@ -224,7 +224,7 @@ class OpaqueBrowserFrameViewLayoutTest : public views::ViewsTestBase {
   }
 
   void AddAvatarLabel() {
-    avatar_label_ = new views::MenuButton(NULL, string16(), NULL, false);
+    avatar_label_ = new views::MenuButton(NULL, base::string16(), NULL, false);
     avatar_label_->set_id(VIEW_ID_AVATAR_LABEL);
     root_view_->AddChildView(avatar_label_);
 
@@ -233,7 +233,8 @@ class OpaqueBrowserFrameViewLayoutTest : public views::ViewsTestBase {
   }
 
   void AddNewAvatarButton() {
-   new_avatar_button_ = new views::MenuButton(NULL, string16(), NULL, false);
+   new_avatar_button_ =
+       new views::MenuButton(NULL, base::string16(), NULL, false);
    new_avatar_button_->set_id(VIEW_ID_NEW_AVATAR_BUTTON);
    root_view_->AddChildView(new_avatar_button_);
   }
diff --git a/chrome/browser/ui/views/frame/system_menu_model_delegate.h b/chrome/browser/ui/views/frame/system_menu_model_delegate.h
index e2c5ba0..15b8bb6 100644
--- a/chrome/browser/ui/views/frame/system_menu_model_delegate.h
+++ b/chrome/browser/ui/views/frame/system_menu_model_delegate.h
@@ -26,7 +26,7 @@ class SystemMenuModelDelegate : public ui::SimpleMenuModel::Delegate {
       int command_id,
       ui::Accelerator* accelerator) OVERRIDE;
   virtual bool IsItemForCommandIdDynamic(int command_id) const OVERRIDE;
-  virtual string16 GetLabelForCommandId(int command_id) const OVERRIDE;
+  virtual base::string16 GetLabelForCommandId(int command_id) const OVERRIDE;
   virtual void ExecuteCommand(int command_id, int event_flags) OVERRIDE;
 
  private:
diff --git a/chrome/browser/ui/views/hung_renderer_view.cc b/chrome/browser/ui/views/hung_renderer_view.cc
index bba8065..5986aa6 100644
--- a/chrome/browser/ui/views/hung_renderer_view.cc
+++ b/chrome/browser/ui/views/hung_renderer_view.cc
@@ -124,7 +124,7 @@ int HungPagesTableModel::RowCount() {
 
 string16 HungPagesTableModel::GetText(int row, int column_id) {
   DCHECK(row >= 0 && row < RowCount());
-  string16 title = tab_observers_[row]->web_contents()->GetTitle();
+  base::string16 title = tab_observers_[row]->web_contents()->GetTitle();
   if (title.empty())
     title = CoreTabHelper::GetDefaultTitle();
   // TODO(xji): Consider adding a special case if the title text is a URL,
diff --git a/chrome/browser/ui/views/hung_renderer_view.h b/chrome/browser/ui/views/hung_renderer_view.h
index 8cd912d..2f4c945 100644
--- a/chrome/browser/ui/views/hung_renderer_view.h
+++ b/chrome/browser/ui/views/hung_renderer_view.h
@@ -49,7 +49,7 @@ class HungPagesTableModel : public ui::TableModel, public views::TableGrouper {
 
   // Overridden from ui::TableModel:
   virtual int RowCount() OVERRIDE;
-  virtual string16 GetText(int row, int column_id) OVERRIDE;
+  virtual base::string16 GetText(int row, int column_id) OVERRIDE;
   virtual gfx::ImageSkia GetIcon(int row) OVERRIDE;
   virtual void SetObserver(ui::TableModelObserver* observer) OVERRIDE;
 
@@ -120,10 +120,11 @@ class HungRendererDialogView : public views::DialogDelegateView,
   virtual void EndForWebContents(content::WebContents* contents);
 
   // views::DialogDelegateView overrides:
-  virtual string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
   virtual void WindowClosing() OVERRIDE;
   virtual int GetDialogButtons() const OVERRIDE;
-  virtual string16 GetDialogButtonLabel(ui::DialogButton button) const OVERRIDE;
+  virtual base::string16 GetDialogButtonLabel(
+      ui::DialogButton button) const OVERRIDE;
   virtual views::View* CreateExtraView() OVERRIDE;
   virtual bool Accept(bool window_closing)  OVERRIDE;
   virtual bool UseNewStyleForThisDialog() const OVERRIDE;
diff --git a/chrome/browser/ui/views/location_bar/location_bar_view.cc b/chrome/browser/ui/views/location_bar/location_bar_view.cc
index 9912ff1..fedebf5b 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.cc
@@ -360,7 +360,7 @@ void LocationBarView::Init() {
   star_view_->SetVisible(false);
   AddChildView(star_view_);
 
-  search_button_ = new views::LabelButton(this, string16());
+  search_button_ = new views::LabelButton(this, base::string16());
   search_button_->set_triggerable_event_flags(
       ui::EF_LEFT_MOUSE_BUTTON | ui::EF_MIDDLE_MOUSE_BUTTON);
   search_button_->SetStyle(views::Button::STYLE_BUTTON);
diff --git a/chrome/browser/ui/views/message_center/web_notification_tray.cc b/chrome/browser/ui/views/message_center/web_notification_tray.cc
index 88124f3..7268b5d 100644
--- a/chrome/browser/ui/views/message_center/web_notification_tray.cc
+++ b/chrome/browser/ui/views/message_center/web_notification_tray.cc
@@ -237,9 +237,9 @@ void WebNotificationTray::UpdateStatusIcon() {
 
   int unread_notifications = message_center()->UnreadNotificationCount();
 
-  string16 tool_tip;
+  base::string16 tool_tip;
   if (unread_notifications > 0) {
-    string16 str_unread_count = base::FormatNumber(unread_notifications);
+    base::string16 str_unread_count = base::FormatNumber(unread_notifications);
     tool_tip = l10n_util::GetStringFUTF16(IDS_MESSAGE_CENTER_TOOLTIP_UNREAD,
                                           str_unread_count);
   } else {
@@ -320,7 +320,7 @@ MessageCenterTray* WebNotificationTray::GetMessageCenterTray() {
 }
 
 void WebNotificationTray::CreateStatusIcon(const gfx::ImageSkia& image,
-                                           const string16& tool_tip) {
+                                           const base::string16& tool_tip) {
   if (status_icon_)
     return;
 
diff --git a/chrome/browser/ui/views/message_center/web_notification_tray.h b/chrome/browser/ui/views/message_center/web_notification_tray.h
index 15fea40..b2df8dc 100644
--- a/chrome/browser/ui/views/message_center/web_notification_tray.h
+++ b/chrome/browser/ui/views/message_center/web_notification_tray.h
@@ -87,7 +87,8 @@ class WebNotificationTray : public message_center::MessageCenterTrayDelegate,
 
   PositionInfo GetPositionInfo();
 
-  void CreateStatusIcon(const gfx::ImageSkia& image, const string16& tool_tip);
+  void CreateStatusIcon(const gfx::ImageSkia& image,
+                        const base::string16& tool_tip);
   void DestroyStatusIcon();
   void AddQuietModeMenu(StatusIcon* status_icon);
   MessageCenterWidgetDelegate* GetMessageCenterWidgetDelegateForTest();
diff --git a/chrome/browser/ui/views/message_center/web_notification_tray_browsertest.cc b/chrome/browser/ui/views/message_center/web_notification_tray_browsertest.cc
index 0f413fa..d7c740c 100644
--- a/chrome/browser/ui/views/message_center/web_notification_tray_browsertest.cc
+++ b/chrome/browser/ui/views/message_center/web_notification_tray_browsertest.cc
@@ -67,7 +67,7 @@ class WebNotificationTrayTest : public InProcessBrowserTest {
                                 ASCIIToUTF16("Test Web Notification"),
                                 ASCIIToUTF16("Notification message body."),
                                 blink::WebTextDirectionDefault,
-                                string16(),
+                                base::string16(),
                                 ASCIIToUTF16(replace_id),
                                 new TestNotificationDelegate(id));
 
@@ -82,7 +82,7 @@ class WebNotificationTrayTest : public InProcessBrowserTest {
                                 ASCIIToUTF16("Updated Web Notification"),
                                 ASCIIToUTF16("Updated message body."),
                                 blink::WebTextDirectionDefault,
-                                string16(),
+                                base::string16(),
                                 ASCIIToUTF16(replace_id),
                                 new TestNotificationDelegate(new_id));
 
diff --git a/chrome/browser/ui/views/passwords/manage_password_item_view.cc b/chrome/browser/ui/views/passwords/manage_password_item_view.cc
index e1e7aba..3779b75 100644
--- a/chrome/browser/ui/views/passwords/manage_password_item_view.cc
+++ b/chrome/browser/ui/views/passwords/manage_password_item_view.cc
@@ -69,7 +69,7 @@ ManagePasswordItemView::ManagePasswordItemView(
   label_2_->SetEnabled(false);
   label_2_->SetUnderline(false);
 
-  delete_button_ = new views::LabelButton(this, string16());
+  delete_button_ = new views::LabelButton(this, base::string16());
   delete_button_->SetStyle(views::Button::STYLE_TEXTBUTTON);
   delete_button_->SetImage(views::Button::STATE_NORMAL,
                            *rb->GetImageSkiaNamed(IDR_CLOSE_2));
@@ -92,10 +92,10 @@ ManagePasswordItemView::ManagePasswordItemView(
 
 // static
 string16 ManagePasswordItemView::GetPasswordDisplayString(
-    const string16& password) {
+    const base::string16& password) {
   const wchar_t kPasswordBullet = 0x2022;
   const size_t kMaxPasswordChar = 22;
-  return string16(std::min(password.length(), kMaxPasswordChar),
+  return base::string16(std::min(password.length(), kMaxPasswordChar),
                   kPasswordBullet);
 }
 
diff --git a/chrome/browser/ui/views/passwords/manage_password_item_view.h b/chrome/browser/ui/views/passwords/manage_password_item_view.h
index 75139e0..d53c486 100644
--- a/chrome/browser/ui/views/passwords/manage_password_item_view.h
+++ b/chrome/browser/ui/views/passwords/manage_password_item_view.h
@@ -25,7 +25,8 @@ class ManagePasswordItemView : public views::View,
       int field_1_width,
       int field_2_width);
 
-  static string16 GetPasswordDisplayString(const string16& password);
+  static base::string16 GetPasswordDisplayString(
+      const base::string16& password);
 
  private:
   virtual ~ManagePasswordItemView();
diff --git a/chrome/browser/ui/views/passwords/manage_passwords_bubble_view.cc b/chrome/browser/ui/views/passwords/manage_passwords_bubble_view.cc
index 159d3ff..4a38203c 100644
--- a/chrome/browser/ui/views/passwords/manage_passwords_bubble_view.cc
+++ b/chrome/browser/ui/views/passwords/manage_passwords_bubble_view.cc
@@ -35,7 +35,7 @@ void UpdateBiggestWidth(const autofill::PasswordForm& password_form,
                         int* biggest_width) {
   ui::ResourceBundle* rb = &ui::ResourceBundle::GetSharedInstance();
   gfx::FontList font_list(rb->GetFontList(ui::ResourceBundle::BaseFont));
-  string16 display_string(username ?
+  base::string16 display_string(username ?
       password_form.username_value :
       ManagePasswordItemView::GetPasswordDisplayString(
           password_form.password_value));
diff --git a/chrome/browser/ui/views/passwords/manage_passwords_icon_view.cc b/chrome/browser/ui/views/passwords/manage_passwords_icon_view.cc
index b58e683..e1ad5e7 100644
--- a/chrome/browser/ui/views/passwords/manage_passwords_icon_view.cc
+++ b/chrome/browser/ui/views/passwords/manage_passwords_icon_view.cc
@@ -57,7 +57,7 @@ void ManagePasswordsIconView::SetTooltip(bool password_to_be_saved) {
 }
 
 bool ManagePasswordsIconView::GetTooltipText(const gfx::Point& p,
-                                             string16* tooltip) const {
+                                             base::string16* tooltip) const {
   // Don't show tooltip if the password bubble is displayed.
   return !ManagePasswordsBubbleView::IsShowing() &&
       ImageView::GetTooltipText(p, tooltip);
diff --git a/chrome/browser/ui/views/passwords/manage_passwords_icon_view.h b/chrome/browser/ui/views/passwords/manage_passwords_icon_view.h
index 44147d2..a215a73 100644
--- a/chrome/browser/ui/views/passwords/manage_passwords_icon_view.h
+++ b/chrome/browser/ui/views/passwords/manage_passwords_icon_view.h
@@ -37,7 +37,7 @@ class ManagePasswordsIconView : public views::ImageView {
  private:
   // views::ImageView:
   virtual bool GetTooltipText(const gfx::Point& p,
-                              string16* tooltip) const OVERRIDE;
+                              base::string16* tooltip) const OVERRIDE;
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
diff --git a/chrome/browser/ui/views/ssl_client_certificate_selector.h b/chrome/browser/ui/views/ssl_client_certificate_selector.h
index 17f35e5..2056b52 100644
--- a/chrome/browser/ui/views/ssl_client_certificate_selector.h
+++ b/chrome/browser/ui/views/ssl_client_certificate_selector.h
@@ -56,7 +56,7 @@ class SSLClientCertificateSelector : public SSLClientAuthObserver,
 
   // DialogDelegateView:
   virtual bool CanResize() const OVERRIDE;
-  virtual string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
   virtual void DeleteDelegate() OVERRIDE;
   virtual bool IsDialogButtonEnabled(ui::DialogButton button) const OVERRIDE;
   virtual bool Cancel() OVERRIDE;
diff --git a/chrome/browser/ui/views/status_bubble_views.h b/chrome/browser/ui/views/status_bubble_views.h
index c1bdc13..c0f66a2 100644
--- a/chrome/browser/ui/views/status_bubble_views.h
+++ b/chrome/browser/ui/views/status_bubble_views.h
@@ -54,7 +54,7 @@ class StatusBubbleViews : public StatusBubble {
   void SetBubbleWidth(int width);
 
   // Overridden from StatusBubble:
-  virtual void SetStatus(const string16& status) OVERRIDE;
+  virtual void SetStatus(const base::string16& status) OVERRIDE;
   virtual void SetURL(const GURL& url, const std::string& languages) OVERRIDE;
   virtual void Hide() OVERRIDE;
   virtual void MouseMoved(const gfx::Point& location,
@@ -94,10 +94,10 @@ class StatusBubbleViews : public StatusBubble {
   int GetMaxStatusBubbleWidth();
 
   // The status text we want to display when there are no URLs to display.
-  string16 status_text_;
+  base::string16 status_text_;
 
   // The url we want to display when there is no status text to display.
-  string16 url_text_;
+  base::string16 url_text_;
 
   // The original, non-elided URL.
   GURL url_;
diff --git a/chrome/browser/ui/views/tab_modal_confirm_dialog_views.h b/chrome/browser/ui/views/tab_modal_confirm_dialog_views.h
index 06f0610..100a474 100644
--- a/chrome/browser/ui/views/tab_modal_confirm_dialog_views.h
+++ b/chrome/browser/ui/views/tab_modal_confirm_dialog_views.h
@@ -35,8 +35,9 @@ class TabModalConfirmDialogViews : public TabModalConfirmDialog,
                              content::WebContents* web_contents);
 
   // views::DialogDelegate:
-  virtual string16 GetWindowTitle() const OVERRIDE;
-  virtual string16 GetDialogButtonLabel(ui::DialogButton button) const OVERRIDE;
+  virtual base::string16 GetWindowTitle() const OVERRIDE;
+  virtual base::string16 GetDialogButtonLabel(
+      ui::DialogButton button) const OVERRIDE;
   virtual bool Cancel() OVERRIDE;
   virtual bool Accept() OVERRIDE;
   virtual bool Close() OVERRIDE;
diff --git a/chrome/browser/ui/views/website_settings/permission_selector_view.cc b/chrome/browser/ui/views/website_settings/permission_selector_view.cc
index 0436925..2e25363 100644
--- a/chrome/browser/ui/views/website_settings/permission_selector_view.cc
+++ b/chrome/browser/ui/views/website_settings/permission_selector_view.cc
@@ -54,7 +54,7 @@ class PermissionMenuButton : public views::MenuButton,
   // |PermissionMenuButton|. If the |show_menu_marker| flag is true, then a
   // small icon is be displayed next to the button |text|, indicating that the
   // button opens a drop down menu.
-  PermissionMenuButton(const string16& text,
+  PermissionMenuButton(const base::string16& text,
                        PermissionMenuModel* model,
                        bool show_menu_marker);
   virtual ~PermissionMenuButton();
@@ -63,7 +63,7 @@ class PermissionMenuButton : public views::MenuButton,
   virtual gfx::Size GetPreferredSize() OVERRIDE;
 
   // Overridden from views::TextButton.
-  virtual void SetText(const string16& text) OVERRIDE;
+  virtual void SetText(const base::string16& text) OVERRIDE;
 
   // Overridden from views::View.
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
@@ -83,7 +83,7 @@ class PermissionMenuButton : public views::MenuButton,
 // PermissionMenuButton
 ///////////////////////////////////////////////////////////////////////////////
 
-PermissionMenuButton::PermissionMenuButton(const string16& text,
+PermissionMenuButton::PermissionMenuButton(const base::string16& text,
                                            PermissionMenuModel* model,
                                            bool show_menu_marker)
     : MenuButton(NULL, text, this, show_menu_marker),
@@ -115,7 +115,7 @@ gfx::Size PermissionMenuButton::GetPreferredSize() {
   return prefsize;
 }
 
-void PermissionMenuButton::SetText(const string16& text) {
+void PermissionMenuButton::SetText(const base::string16& text) {
   MenuButton::SetText(text);
   SizeToPreferredSize();
 }
diff --git a/chrome/browser/ui/views/website_settings/website_settings_popup_view.cc b/chrome/browser/ui/views/website_settings/website_settings_popup_view.cc
index 085063d..c6afe7d 100644
--- a/chrome/browser/ui/views/website_settings/website_settings_popup_view.cc
+++ b/chrome/browser/ui/views/website_settings/website_settings_popup_view.cc
@@ -116,11 +116,11 @@ class PopupHeaderView : public views::View {
   virtual ~PopupHeaderView();
 
   // Sets the name of the site's identity.
-  void SetIdentityName(const string16& name);
+  void SetIdentityName(const base::string16& name);
 
   // Sets the |status_text| for the identity check of this site and the
   // |text_color|.
-  void SetIdentityStatus(const string16& status_text, SkColor text_color);
+  void SetIdentityStatus(const base::string16& status_text, SkColor text_color);
 
  private:
   // The label that displays the name of the site's identity.
@@ -173,7 +173,7 @@ PopupHeaderView::PopupHeaderView(views::ButtonListener* close_button_listener)
   layout->AddPaddingRow(0, kHeaderPaddingTop);
 
   layout->StartRow(0, label_column);
-  name_ = new views::Label(string16());
+  name_ = new views::Label(base::string16());
   gfx::Font headline_font(name_->font().GetFontName(), kIdentityNameFontSize);
   name_->SetFont(headline_font.DeriveFont(0, gfx::Font::BOLD));
   layout->AddView(name_, 1, 1, views::GridLayout::LEADING,
@@ -193,7 +193,7 @@ PopupHeaderView::PopupHeaderView(views::ButtonListener* close_button_listener)
   layout->AddPaddingRow(0, kHeaderRowSpacing);
 
   layout->StartRow(0, label_column);
-  status_ = new views::Label(string16());
+  status_ = new views::Label(base::string16());
   layout->AddView(status_,
                   1,
                   1,
@@ -206,11 +206,11 @@ PopupHeaderView::PopupHeaderView(views::ButtonListener* close_button_listener)
 PopupHeaderView::~PopupHeaderView() {
 }
 
-void PopupHeaderView::SetIdentityName(const string16& name) {
+void PopupHeaderView::SetIdentityName(const base::string16& name) {
   name_->SetText(name);
 }
 
-void PopupHeaderView::SetIdentityStatus(const string16& status,
+void PopupHeaderView::SetIdentityStatus(const base::string16& status,
                                         SkColor text_color) {
   status_->SetText(status);
   status_->SetEnabledColor(text_color);
@@ -428,7 +428,7 @@ void WebsiteSettingsPopupView::SetCookieInfo(
   for (CookieInfoList::const_iterator i(cookie_info_list.begin());
        i != cookie_info_list.end();
        ++i) {
-    string16 label_text = l10n_util::GetStringFUTF16(
+    base::string16 label_text = l10n_util::GetStringFUTF16(
         IDS_WEBSITE_SETTINGS_SITE_DATA_STATS_LINE,
         UTF8ToUTF16(i->cookie_source),
         base::IntToString16(i->allowed),
@@ -492,7 +492,7 @@ void WebsiteSettingsPopupView::SetPermissionInfo(
 
 void WebsiteSettingsPopupView::SetIdentityInfo(
     const IdentityInfo& identity_info) {
-  string16 identity_status_text;
+  base::string16 identity_status_text;
   SkColor text_color = SK_ColorBLACK;
   switch (identity_info.identity_status) {
     case WebsiteSettings::SITE_IDENTITY_STATUS_CERT:
@@ -518,7 +518,7 @@ void WebsiteSettingsPopupView::SetIdentityInfo(
   // site's identity was verified, then the headline contains the organization
   // name from the provided certificate. If the organization name is not
   // available than the hostname of the site is used instead.
-  string16 headline;
+  base::string16 headline;
   if (identity_info.cert_id) {
     cert_id_ = identity_info.cert_id;
     certificate_dialog_link_ = new views::Link(
@@ -529,14 +529,14 @@ void WebsiteSettingsPopupView::SetIdentityInfo(
   ResetConnectionSection(
       identity_info_content_,
       WebsiteSettingsUI::GetIdentityIcon(identity_info.identity_status),
-      string16(), // The identity section has no headline.
+      base::string16(), // The identity section has no headline.
       UTF8ToUTF16(identity_info.identity_status_description),
       certificate_dialog_link_);
 
   ResetConnectionSection(
       connection_info_content_,
       WebsiteSettingsUI::GetConnectionIcon(identity_info.connection_status),
-      string16(),  // The connection section has no headline.
+      base::string16(),  // The connection section has no headline.
       UTF8ToUTF16(identity_info.connection_status_description),
       NULL);
 
@@ -545,7 +545,8 @@ void WebsiteSettingsPopupView::SetIdentityInfo(
   SizeToContents();
 }
 
-void WebsiteSettingsPopupView::SetFirstVisit(const string16& first_visit) {
+void WebsiteSettingsPopupView::SetFirstVisit(
+    const base::string16& first_visit) {
   ResetConnectionSection(
       page_info_content_,
       WebsiteSettingsUI::GetFirstVisitIcon(first_visit),
@@ -623,7 +624,7 @@ views::View* WebsiteSettingsPopupView::CreateConnectionTab() {
 }
 
 views::View* WebsiteSettingsPopupView::CreateSection(
-    const string16& headline_text,
+    const base::string16& headline_text,
     views::View* content,
     views::Link* link) {
   views::View* container = new views::View();
@@ -665,8 +666,8 @@ views::View* WebsiteSettingsPopupView::CreateSection(
 void WebsiteSettingsPopupView::ResetConnectionSection(
     views::View* section_container,
     const gfx::Image& icon,
-    const string16& headline,
-    const string16& text,
+    const base::string16& headline,
+    const base::string16& text,
     views::Link* link) {
   section_container->RemoveAllChildViews(true);
 
diff --git a/chrome/browser/ui/views/website_settings/website_settings_popup_view.h b/chrome/browser/ui/views/website_settings/website_settings_popup_view.h
index 15d0a42..c3a4e9b 100644
--- a/chrome/browser/ui/views/website_settings/website_settings_popup_view.h
+++ b/chrome/browser/ui/views/website_settings/website_settings_popup_view.h
@@ -85,7 +85,7 @@ class WebsiteSettingsPopupView
   virtual void SetPermissionInfo(
       const PermissionInfoList& permission_info_list) OVERRIDE;
   virtual void SetIdentityInfo(const IdentityInfo& identity_info) OVERRIDE;
-  virtual void SetFirstVisit(const string16& first_visit) OVERRIDE;
+  virtual void SetFirstVisit(const base::string16& first_visit) OVERRIDE;
   virtual void SetSelectedTab(TabId tab_id) OVERRIDE;
 
   // Creates the contents of the "Permissions" tab. The ownership of the
@@ -100,7 +100,7 @@ class WebsiteSettingsPopupView
   // section |contents| and an optional |link|. This method creates a section
   // for the given |headline|, |contents| and |link|. |link| can be NULL if the
   // section should not contain a link.
-  views::View* CreateSection(const string16& headline,
+  views::View* CreateSection(const base::string16& headline,
                              views::View* contents,
                              views::Link* link) WARN_UNUSED_RESULT;
 
@@ -112,8 +112,8 @@ class WebsiteSettingsPopupView
   // the views hierarchy. If the |link| is NULL then no link is be displayed.
   void ResetConnectionSection(views::View* section_container,
                               const gfx::Image& icon,
-                              const string16& headline,
-                              const string16& text,
+                              const base::string16& headline,
+                              const base::string16& text,
                               views::Link* link);
   // Handles LinkClicked asynchronously.
   void HandleLinkClickedAsync(views::Link* source);
diff --git a/chrome/browser/ui/webui/about_ui.cc b/chrome/browser/ui/webui/about_ui.cc
index 1733570..29c2f12 100644
--- a/chrome/browser/ui/webui/about_ui.cc
+++ b/chrome/browser/ui/webui/about_ui.cc
@@ -904,7 +904,7 @@ void AboutMemoryHandler::OnDetailsAvailable() {
   const std::vector<ProcessData>& browser_processes = processes();
 
   // Aggregate per-process data into browser summary data.
-  string16 log_string;
+  base::string16 log_string;
   for (size_t index = 0; index < browser_processes.size(); index++) {
     if (browser_processes[index].processes.empty())
       continue;
diff --git a/chrome/browser/ui/webui/certificate_viewer_webui.h b/chrome/browser/ui/webui/certificate_viewer_webui.h
index 410300d..f546b10 100644
--- a/chrome/browser/ui/webui/certificate_viewer_webui.h
+++ b/chrome/browser/ui/webui/certificate_viewer_webui.h
@@ -41,7 +41,7 @@ class CertificateViewerDialog : private ui::WebDialogDelegate {
  private:
   // Overridden from ui::WebDialogDelegate:
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
-  virtual string16 GetDialogTitle() const OVERRIDE;
+  virtual base::string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<content::WebUIMessageHandler*>* handlers) const OVERRIDE;
@@ -61,7 +61,7 @@ class CertificateViewerDialog : private ui::WebDialogDelegate {
   ConstrainedWebDialogDelegate* dialog_;
 
   // The title of the certificate viewer dialog, Certificate Viewer: CN.
-  string16 title_;
+  base::string16 title_;
 
   DISALLOW_COPY_AND_ASSIGN(CertificateViewerDialog);
 };
diff --git a/chrome/browser/ui/webui/chromeos/imageburner/imageburner_ui.cc b/chrome/browser/ui/webui/chromeos/imageburner/imageburner_ui.cc
index 08b3146..0a1c11f 100644
--- a/chrome/browser/ui/webui/chromeos/imageburner/imageburner_ui.cc
+++ b/chrome/browser/ui/webui/chromeos/imageburner/imageburner_ui.cc
@@ -142,7 +142,7 @@ class WebUIHandler
 
   // BurnController::Delegate override.
   virtual void OnDeviceTooSmall(int64 device_size) OVERRIDE {
-    string16 size;
+    base::string16 size;
     GetDataSizeText(device_size, &size);
     StringValue device_size_text(size);
     web_ui()->CallJavascriptFunction("browserBridge.reportDeviceTooSmall",
@@ -153,7 +153,7 @@ class WebUIHandler
   virtual void OnProgress(ProgressType progress_type,
                           int64 amount_finished,
                           int64 amount_total) OVERRIDE {
-    const string16 time_remaining_text =
+    const base::string16 time_remaining_text =
         l10n_util::GetStringUTF16(IDS_IMAGEBURN_PROGRESS_TIME_UNKNOWN);
     SendProgressSignal(progress_type, amount_finished, amount_total,
                        time_remaining_text);
@@ -165,7 +165,7 @@ class WebUIHandler
       int64 amount_finished,
       int64 amount_total,
       const base::TimeDelta& time_remaining) OVERRIDE {
-    const string16 time_remaining_text = l10n_util::GetStringFUTF16(
+    const base::string16 time_remaining_text = l10n_util::GetStringFUTF16(
         IDS_IMAGEBURN_DOWNLOAD_TIME_REMAINING,
         ui::TimeFormat::TimeRemaining(time_remaining));
     SendProgressSignal(progress_type, amount_finished, amount_total,
@@ -185,7 +185,7 @@ class WebUIHandler
  private:
   void CreateDiskValue(const disks::DiskMountManager::Disk& disk,
                        DictionaryValue* disk_value) {
-    string16 label = ASCIIToUTF16(disk.drive_label());
+    base::string16 label = ASCIIToUTF16(disk.drive_label());
     base::i18n::AdjustStringForLocaleDirection(&label);
     disk_value->SetString(std::string(kPropertyLabel), label);
     disk_value->SetString(std::string(kPropertyFilePath), disk.file_path());
@@ -235,7 +235,7 @@ class WebUIHandler
   void SendProgressSignal(ProgressType progress_type,
                           int64 amount_finished,
                           int64 amount_total,
-                          const string16& time_remaining_text) {
+                          const base::string16& time_remaining_text) {
     DictionaryValue progress;
     int progress_message_id = 0;
     switch (progress_type) {
@@ -257,7 +257,7 @@ class WebUIHandler
     progress.SetInteger("amountFinished", amount_finished);
     progress.SetInteger("amountTotal", amount_total);
     if (amount_total != 0) {
-      string16 progress_text;
+      base::string16 progress_text;
       GetProgressText(progress_message_id, amount_finished, amount_total,
                       &progress_text);
       progress.SetString("progressText", progress_text);
@@ -270,7 +270,7 @@ class WebUIHandler
   }
 
   // size_text should be previously created.
-  void GetDataSizeText(int64 size, string16* size_text) {
+  void GetDataSizeText(int64 size, base::string16* size_text) {
     *size_text = ui::FormatBytes(size);
     base::i18n::AdjustStringForLocaleDirection(size_text);
   }
@@ -279,10 +279,10 @@ class WebUIHandler
   void GetProgressText(int message_id,
                        int64 amount_finished,
                        int64 amount_total,
-                       string16* progress_text) {
-    string16 finished;
+                       base::string16* progress_text) {
+    base::string16 finished;
     GetDataSizeText(amount_finished, &finished);
-    string16 total;
+    base::string16 total;
     GetDataSizeText(amount_total, &total);
     *progress_text = l10n_util::GetStringFUTF16(message_id, finished, total);
   }
diff --git a/chrome/browser/ui/webui/chromeos/login/app_launch_splash_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/app_launch_splash_screen_handler.cc
index e95fa2e..aaf1913 100644
--- a/chrome/browser/ui/webui/chromeos/login/app_launch_splash_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/app_launch_splash_screen_handler.cc
@@ -57,7 +57,7 @@ void AppLaunchSplashScreenHandler::DeclareLocalizedValues(
   builder->Add("appStartMessage", IDS_APP_START_NETWORK_WAIT_MESSAGE);
   builder->Add("configureNetwork", IDS_APP_START_CONFIGURE_NETWORK);
 
-  const string16 product_os_name =
+  const base::string16 product_os_name =
       l10n_util::GetStringUTF16(IDS_SHORT_PRODUCT_OS_NAME);
   builder->Add(
       "shortcutInfo",
diff --git a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
index 2fd1450..d530039 100644
--- a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
@@ -22,7 +22,7 @@ void LocalizedValuesBuilder::Add(const std::string& key,
 }
 
 void LocalizedValuesBuilder::Add(const std::string& key,
-                                 const string16& message) {
+                                 const base::string16& message) {
   dict_->SetString(key, message);
 }
 
@@ -33,15 +33,15 @@ void LocalizedValuesBuilder::Add(const std::string& key, int message_id) {
 
 void LocalizedValuesBuilder::AddF(const std::string& key,
                                   int message_id,
-                                  const string16& a) {
+                                  const base::string16& a) {
   dict_->SetString(key,
                    l10n_util::GetStringFUTF16(message_id, a));
 }
 
 void LocalizedValuesBuilder::AddF(const std::string& key,
                                   int message_id,
-                                  const string16& a,
-                                  const string16& b) {
+                                  const base::string16& a,
+                                  const base::string16& b) {
   dict_->SetString(key,
                    l10n_util::GetStringFUTF16(message_id, a, b));
 }
diff --git a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.h
index 4baf62c..9efddca 100644
--- a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.h
@@ -34,7 +34,7 @@ class LocalizedValuesBuilder {
 
   // Method to declare localized value. |key| is the i18n key used in html.
   // |message| is text of the message.
-  void Add(const std::string& key, const string16& message);
+  void Add(const std::string& key, const base::string16& message);
 
   // Method to declare localized value. |key| is the i18n key used in html.
   // |message_id| is a resource id of message.
@@ -45,15 +45,15 @@ class LocalizedValuesBuilder {
   // one format parameter subsituted by |a|.
   void AddF(const std::string& key,
             int message_id,
-            const string16& a);
+            const base::string16& a);
 
   // Method to declare localized value. |key| is the i18n key used in html.
   // |message_id| is a resource id of message. Message is expected to have
   // two format parameters subsituted by |a| and |b| respectively.
   void AddF(const std::string& key,
             int message_id,
-            const string16& a,
-            const string16& b);
+            const base::string16& a,
+            const base::string16& b);
 
   // Method to declare localized value. |key| is the i18n key used in html.
   // |message_id| is a resource id of message. Message is expected to have
diff --git a/chrome/browser/ui/webui/chromeos/login/base_screen_handler_utils.h b/chrome/browser/ui/webui/chromeos/login/base_screen_handler_utils.h
index f39c82a..05bfaec 100644
--- a/chrome/browser/ui/webui/chromeos/login/base_screen_handler_utils.h
+++ b/chrome/browser/ui/webui/chromeos/login/base_screen_handler_utils.h
@@ -86,7 +86,7 @@ inline base::StringValue MakeValue(const std::string& v) {
   return base::StringValue(v);
 }
 
-inline base::StringValue MakeValue(const string16& v) {
+inline base::StringValue MakeValue(const base::string16& v) {
   return base::StringValue(v);
 }
 
diff --git a/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.cc
index 3952383..8d5f98a 100644
--- a/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.cc
@@ -219,7 +219,7 @@ void LocallyManagedUserCreationScreenHandler::ShowManagerPasswordError() {
 
 void LocallyManagedUserCreationScreenHandler::ShowStatusMessage(
     bool is_progress,
-    const string16& message) {
+    const base::string16& message) {
   if (is_progress)
     CallJS("showProgress", message);
   else
@@ -235,9 +235,9 @@ void LocallyManagedUserCreationScreenHandler::ShowTutorialPage() {
 }
 
 void LocallyManagedUserCreationScreenHandler::ShowErrorPage(
-    const string16& title,
-    const string16& message,
-    const string16& button_text) {
+    const base::string16& title,
+    const base::string16& message,
+    const base::string16& button_text) {
   CallJS("showErrorPage", title, message, button_text);
 }
 
@@ -269,7 +269,7 @@ void LocallyManagedUserCreationScreenHandler::HandleImportUserSelected(
 }
 
 void LocallyManagedUserCreationScreenHandler::HandleCheckLocallyManagedUserName(
-    const string16& name) {
+    const base::string16& name) {
   std::string user_id;
   if (NULL != UserManager::Get()->GetSupervisedUserManager()->
           FindByDisplayName(CollapseWhitespace(name, true))) {
@@ -289,11 +289,12 @@ void LocallyManagedUserCreationScreenHandler::HandleCheckLocallyManagedUserName(
 }
 
 void LocallyManagedUserCreationScreenHandler::HandleCreateManagedUser(
-    const string16& new_raw_user_name,
+    const base::string16& new_raw_user_name,
     const std::string& new_user_password) {
   if (!delegate_)
     return;
-  const string16 new_user_name = CollapseWhitespace(new_raw_user_name, true);
+  const base::string16 new_user_name =
+      CollapseWhitespace(new_raw_user_name, true);
   if (NULL != UserManager::Get()->GetSupervisedUserManager()->
           FindByDisplayName(new_user_name)) {
     CallJS("managedUserNameError", new_user_name,
diff --git a/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.h
index 55673b2..8fcf3fb 100644
--- a/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/locally_managed_user_creation_screen_handler.h
@@ -38,13 +38,13 @@ class LocallyManagedUserCreationScreenHandler : public BaseScreenHandler {
     // Starts managed user creation flow, with supervised user that would have
     // |display_name| and authenticated by the |managed_user_password|.
     virtual void CreateManagedUser(
-        const string16& display_name,
+        const base::string16& display_name,
         const std::string& managed_user_password) = 0;
 
     // Look up if user with name |display_name| already exist and can be
     // imported. Returns user ID in |out_id|. Returns true if user was found,
     // false otherwise.
-    virtual bool FindUserByDisplayName(const string16& display_name,
+    virtual bool FindUserByDisplayName(const base::string16& display_name,
                                        std::string *out_id) const = 0;
 
     // Starts managed user import flow for user identified with |user_id|.
@@ -81,12 +81,12 @@ class LocallyManagedUserCreationScreenHandler : public BaseScreenHandler {
 
   // Shows progress or error message close in the button area. |is_progress| is
   // true for progress messages and false for error messages.
-  void ShowStatusMessage(bool is_progress, const string16& message);
+  void ShowStatusMessage(bool is_progress, const base::string16& message);
   void ShowTutorialPage();
 
-  void ShowErrorPage(const string16& title,
-                     const string16& message,
-                     const string16& button_text);
+  void ShowErrorPage(const base::string16& title,
+                     const base::string16& message,
+                     const base::string16& button_text);
 
   // Navigates to specified page.
   void ShowPage(const std::string& page);
@@ -104,7 +104,7 @@ class LocallyManagedUserCreationScreenHandler : public BaseScreenHandler {
 
  private:
   // WebUI message handlers.
-  void HandleCheckLocallyManagedUserName(const string16& name);
+  void HandleCheckLocallyManagedUserName(const base::string16& name);
 
   void HandleManagerSelected(const std::string& manager_id);
   void HandleImportUserSelected(const std::string& user_id);
@@ -116,7 +116,7 @@ class LocallyManagedUserCreationScreenHandler : public BaseScreenHandler {
 
   void HandleAuthenticateManager(const std::string& raw_manager_username,
                                  const std::string& manager_password);
-  void HandleCreateManagedUser(const string16& new_raw_user_name,
+  void HandleCreateManagedUser(const base::string16& new_raw_user_name,
                                const std::string& new_user_password);
   void HandleImportSupervisedUser(const std::string& user_id);
   void HandleImportSupervisedUserWithPassword(const std::string& user_id,
@@ -128,7 +128,7 @@ class LocallyManagedUserCreationScreenHandler : public BaseScreenHandler {
   void HandleSelectImage(const std::string& image_url,
                          const std::string& image_type);
 
-  void UpdateText(const std::string& element_id, const string16& text);
+  void UpdateText(const std::string& element_id, const base::string16& text);
 
   Delegate* delegate_;
 
diff --git a/chrome/browser/ui/webui/chromeos/login/network_dropdown.cc b/chrome/browser/ui/webui/chromeos/login/network_dropdown.cc
index e3d6728..5076cc4 100644
--- a/chrome/browser/ui/webui/chromeos/login/network_dropdown.cc
+++ b/chrome/browser/ui/webui/chromeos/login/network_dropdown.cc
@@ -181,7 +181,7 @@ void NetworkDropdown::Refresh() {
 }
 
 void NetworkDropdown::SetNetworkIconAndText() {
-  string16 text;
+  base::string16 text;
   gfx::ImageSkia icon_image;
   bool animating = false;
   ash::network_icon::GetDefaultNetworkImageAndLabel(
diff --git a/chrome/browser/ui/webui/chromeos/login/network_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/network_screen_handler.cc
index 93531f3..603c5c2b 100644
--- a/chrome/browser/ui/webui/chromeos/login/network_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/network_screen_handler.cc
@@ -78,7 +78,7 @@ void NetworkScreenHandler::Show() {
 void NetworkScreenHandler::Hide() {
 }
 
-void NetworkScreenHandler::ShowError(const string16& message) {
+void NetworkScreenHandler::ShowError(const base::string16& message) {
   CallJS("showError", message);
 }
 
@@ -89,8 +89,8 @@ void NetworkScreenHandler::ClearErrors() {
 
 void NetworkScreenHandler::ShowConnectingStatus(
     bool connecting,
-    const string16& network_id) {
-  // string16 connecting_label =
+    const base::string16& network_id) {
+  // base::string16 connecting_label =
   //     l10n_util::GetStringFUTF16(IDS_NETWORK_SELECTION_CONNECTING,
   //                                network_id);
   // CallJS("cr.ui.Oobe.showConnectingStatus",
diff --git a/chrome/browser/ui/webui/chromeos/login/network_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/network_screen_handler.h
index a19486b..56cb8a2 100644
--- a/chrome/browser/ui/webui/chromeos/login/network_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/network_screen_handler.h
@@ -32,10 +32,10 @@ class NetworkScreenHandler : public NetworkScreenActor,
   virtual void PrepareToShow() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void Hide() OVERRIDE;
-  virtual void ShowError(const string16& message) OVERRIDE;
+  virtual void ShowError(const base::string16& message) OVERRIDE;
   virtual void ClearErrors() OVERRIDE;
   virtual void ShowConnectingStatus(bool connecting,
-                                    const string16& network_id) OVERRIDE;
+                                    const base::string16& network_id) OVERRIDE;
   virtual void EnableContinue(bool enabled) OVERRIDE;
 
   // BaseScreenHandler implementation:
diff --git a/chrome/browser/ui/webui/chromeos/mobile_setup_dialog.cc b/chrome/browser/ui/webui/chromeos/mobile_setup_dialog.cc
index 1ad3328..81b1851 100644
--- a/chrome/browser/ui/webui/chromeos/mobile_setup_dialog.cc
+++ b/chrome/browser/ui/webui/chromeos/mobile_setup_dialog.cc
@@ -44,7 +44,7 @@ class MobileSetupDialogDelegate : public WebDialogDelegate {
 
   // WebDialogDelegate overrides.
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
-  virtual string16 GetDialogTitle() const OVERRIDE;
+  virtual base::string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<WebUIMessageHandler*>* handlers) const OVERRIDE;
diff --git a/chrome/browser/ui/webui/chromeos/mobile_setup_ui.cc b/chrome/browser/ui/webui/chromeos/mobile_setup_ui.cc
index df644ab3..486ce96 100644
--- a/chrome/browser/ui/webui/chromeos/mobile_setup_ui.cc
+++ b/chrome/browser/ui/webui/chromeos/mobile_setup_ui.cc
@@ -635,7 +635,7 @@ MobileSetupUI::MobileSetupUI(content::WebUI* web_ui)
 
 void MobileSetupUI::DidCommitProvisionalLoadForFrame(
     int64 frame_id,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& url,
     content::PageTransition transition_type,
@@ -649,11 +649,11 @@ void MobileSetupUI::DidCommitProvisionalLoadForFrame(
 
 void MobileSetupUI::DidFailProvisionalLoad(
     int64 frame_id,
-    const string16& frame_unique_name,
+    const base::string16& frame_unique_name,
     bool is_main_frame,
     const GURL& validated_url,
     int error_code,
-    const string16& error_description,
+    const base::string16& error_description,
     content::RenderViewHost* render_view_host) {
   if (frame_unique_name != UTF8ToUTF16("paymentForm"))
     return;
diff --git a/chrome/browser/ui/webui/chromeos/mobile_setup_ui.h b/chrome/browser/ui/webui/chromeos/mobile_setup_ui.h
index 336d2fd..cbd5541 100644
--- a/chrome/browser/ui/webui/chromeos/mobile_setup_ui.h
+++ b/chrome/browser/ui/webui/chromeos/mobile_setup_ui.h
@@ -21,18 +21,18 @@ class MobileSetupUI : public content::WebUIController,
   // content::WebContentsObserver overrides.
   virtual void DidCommitProvisionalLoadForFrame(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& url,
       content::PageTransition transition_type,
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void DidFailProvisionalLoad(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& validated_url,
       int error_code,
-      const string16& error_description,
+      const base::string16& error_description,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(MobileSetupUI);
diff --git a/chrome/browser/ui/webui/conflicts_ui.cc b/chrome/browser/ui/webui/conflicts_ui.cc
index c5f0a19..cc937aa 100644
--- a/chrome/browser/ui/webui/conflicts_ui.cc
+++ b/chrome/browser/ui/webui/conflicts_ui.cc
@@ -121,7 +121,7 @@ void ConflictsDOMHandler::SendModuleList() {
   // Add the section title and the total count for bad modules found.
   int confirmed_bad = loaded_modules->confirmed_bad_modules_detected();
   int suspected_bad = loaded_modules->suspected_bad_modules_detected();
-  string16 table_title;
+  base::string16 table_title;
   if (!confirmed_bad && !suspected_bad) {
     table_title += l10n_util::GetStringFUTF16(
         IDS_CONFLICTS_CHECK_PAGE_TABLE_TITLE_SUFFIX_ONE,
diff --git a/chrome/browser/ui/webui/downloads_dom_handler.cc b/chrome/browser/ui/webui/downloads_dom_handler.cc
index f964d84..77f3c31 100644
--- a/chrome/browser/ui/webui/downloads_dom_handler.cc
+++ b/chrome/browser/ui/webui/downloads_dom_handler.cc
@@ -151,7 +151,7 @@ DictionaryValue* CreateDownloadItemValue(
   }
 
   // Keep file names as LTR.
-  string16 file_name =
+  base::string16 file_name =
     download_item->GetFileNameToReportUser().LossyDisplayName();
   file_name = base::i18n::GetDisplayStringInLTRDirectionality(file_name);
   file_value->SetString("file_name", file_name);
diff --git a/chrome/browser/ui/webui/extensions/chromeos/kiosk_apps_handler.cc b/chrome/browser/ui/webui/extensions/chromeos/kiosk_apps_handler.cc
index 39ae6a2..3fdaecf 100644
--- a/chrome/browser/ui/webui/extensions/chromeos/kiosk_apps_handler.cc
+++ b/chrome/browser/ui/webui/extensions/chromeos/kiosk_apps_handler.cc
@@ -159,7 +159,7 @@ void KioskAppsHandler::GetLocalizedValues(content::WebUIDataSource* source) {
       "kioskDisableBailoutShortcutWarningBold",
       l10n_util::GetStringUTF16(
           IDS_OPTIONS_KIOSK_DISABLE_BAILOUT_SHORTCUT_WARNING_BOLD));
-  const string16 product_os_name =
+  const base::string16 product_os_name =
       l10n_util::GetStringUTF16(IDS_SHORT_PRODUCT_OS_NAME);
   source->AddString(
       "kioskDisableBailoutShortcutWarning",
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index 7fbafa6..1a757c0 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -233,7 +233,7 @@ base::DictionaryValue* ExtensionSettingsHandler::CreateExtensionDetailValue(
   extension_data->SetBoolean("homepageProvided",
       ManifestURL::GetHomepageURL(extension).is_valid());
 
-  string16 location_text;
+  base::string16 location_text;
   if (Manifest::IsPolicyLocation(extension->location())) {
     location_text = l10n_util::GetStringUTF16(
         IDS_OPTIONS_INSTALL_LOCATION_ENTERPRISE);
@@ -997,7 +997,7 @@ void ExtensionSettingsHandler::HandleLoadUnpackedExtensionMessage(
     const base::ListValue* args) {
   DCHECK(args->empty());
 
-  string16 select_title =
+  base::string16 select_title =
       l10n_util::GetStringUTF16(IDS_EXTENSION_LOAD_FROM_DIRECTORY);
 
   const int kFileTypeIndex = 0;  // No file type information to index.
diff --git a/chrome/browser/ui/webui/extensions/pack_extension_handler.cc b/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
index 4bb3e4e..49f47c4 100644
--- a/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
+++ b/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
@@ -169,7 +169,7 @@ void PackExtensionHandler::HandleSelectFilePathMessage(
     path_to_use = base::FilePath();
   }
 
-  string16 select_title;
+  base::string16 select_title;
   if (operation == "load") {
     select_title = l10n_util::GetStringUTF16(IDS_EXTENSION_LOAD_FROM_DIRECTORY);
   } else if (operation == "pem") {
diff --git a/chrome/browser/ui/webui/flags_ui.cc b/chrome/browser/ui/webui/flags_ui.cc
index 405c7fd..c21350f 100644
--- a/chrome/browser/ui/webui/flags_ui.cc
+++ b/chrome/browser/ui/webui/flags_ui.cc
@@ -84,7 +84,7 @@ content::WebUIDataSource* CreateFlagsUIHTMLSource() {
   } else {
     // The warning will be only shown on ChromeOS, when the current user is not
     // the owner.
-    source->AddString("ownerWarning", string16());
+    source->AddString("ownerWarning", base::string16());
   }
 #endif
 
diff --git a/chrome/browser/ui/webui/flash_ui.cc b/chrome/browser/ui/webui/flash_ui.cc
index cf4aefb..4d6333c 100644
--- a/chrome/browser/ui/webui/flash_ui.cc
+++ b/chrome/browser/ui/webui/flash_ui.cc
@@ -180,14 +180,18 @@ void FlashDOMHandler::OnUploadListAvailable() {
   MaybeRespondToPage();
 }
 
-void AddPair(ListValue* list, const string16& key, const string16& value) {
+void AddPair(ListValue* list,
+             const base::string16& key,
+             const base::string16& value) {
   DictionaryValue* results = new DictionaryValue();
   results->SetString("key", key);
   results->SetString("value", value);
   list->Append(results);
 }
 
-void AddPair(ListValue* list, const string16& key, const std::string& value) {
+void AddPair(ListValue* list,
+             const base::string16& key,
+             const std::string& value) {
   AddPair(list, key, ASCIIToUTF16(value));
 }
 
@@ -275,7 +279,7 @@ void FlashDOMHandler::MaybeRespondToPage() {
         PluginPrefs::GetForProfile(Profile::FromWebUI(web_ui())).get();
     bool found_enabled = false;
     for (size_t i = 0; i < info_array.size(); ++i) {
-      string16 flash_version = info_array[i].version + ASCIIToUTF16(" ") +
+      base::string16 flash_version = info_array[i].version + ASCIIToUTF16(" ") +
                                info_array[i].path.LossyDisplayName();
       if (plugin_prefs->IsPluginEnabled(info_array[i])) {
         // If we have already found an enabled Flash version, this one
@@ -292,7 +296,7 @@ void FlashDOMHandler::MaybeRespondToPage() {
   }
 
   // Crash information.
-  AddPair(list, string16(), "--- Crash data ---");
+  AddPair(list, base::string16(), "--- Crash data ---");
   bool crash_reporting_enabled = CrashesUI::CrashReportingUIEnabled();
   if (crash_reporting_enabled) {
     std::vector<CrashUploadList::UploadInfo> crashes;
@@ -300,7 +304,7 @@ void FlashDOMHandler::MaybeRespondToPage() {
 
     for (std::vector<CrashUploadList::UploadInfo>::iterator i = crashes.begin();
          i != crashes.end(); ++i) {
-      string16 crash_string(ASCIIToUTF16(i->id));
+      base::string16 crash_string(ASCIIToUTF16(i->id));
       crash_string += ASCIIToUTF16(" ");
       crash_string += base::TimeFormatFriendlyDateAndTime(i->time);
       AddPair(list, ASCIIToUTF16("crash id"), crash_string);
@@ -313,7 +317,7 @@ void FlashDOMHandler::MaybeRespondToPage() {
   }
 
   // GPU information.
-  AddPair(list, string16(), "--- GPU information ---");
+  AddPair(list, base::string16(), "--- GPU information ---");
   gpu::GPUInfo gpu_info = GpuDataManager::GetInstance()->GetGPUInfo();
 
   std::string reason;
@@ -344,7 +348,7 @@ void FlashDOMHandler::MaybeRespondToPage() {
   }
 #endif
 
-  AddPair(list, string16(), "--- GPU driver, more information ---");
+  AddPair(list, base::string16(), "--- GPU driver, more information ---");
   AddPair(list,
           ASCIIToUTF16("Vendor Id"),
           base::StringPrintf("0x%04x", gpu_info.gpu.vendor_id));
diff --git a/chrome/browser/ui/webui/help/help_handler.cc b/chrome/browser/ui/webui/help/help_handler.cc
index a42f63f..98c5202 100644
--- a/chrome/browser/ui/webui/help/help_handler.cc
+++ b/chrome/browser/ui/webui/help/help_handler.cc
@@ -227,19 +227,19 @@ void HelpHandler::GetLocalizedValues(content::WebUIDataSource* source) {
        l10n_util::GetStringFUTF16(IDS_ABOUT_VERSION_COPYRIGHT,
                                   base::IntToString16(exploded_time.year)));
 
-  string16 license = l10n_util::GetStringFUTF16(
+  base::string16 license = l10n_util::GetStringFUTF16(
       IDS_ABOUT_VERSION_LICENSE,
       ASCIIToUTF16(chrome::kChromiumProjectURL),
       ASCIIToUTF16(chrome::kChromeUICreditsURL));
   source->AddString("productLicense", license);
 
 #if defined(OS_CHROMEOS)
-  string16 os_license = l10n_util::GetStringFUTF16(
+  base::string16 os_license = l10n_util::GetStringFUTF16(
       IDS_ABOUT_CROS_VERSION_LICENSE,
       ASCIIToUTF16(chrome::kChromeUIOSCreditsURL));
   source->AddString("productOsLicense", os_license);
 
-  string16 product_name = l10n_util::GetStringUTF16(IDS_PRODUCT_OS_NAME);
+  base::string16 product_name = l10n_util::GetStringUTF16(IDS_PRODUCT_OS_NAME);
   source->AddString(
       "channelChangePageDelayedChangeMessage",
       l10n_util::GetStringFUTF16(
@@ -257,7 +257,7 @@ void HelpHandler::GetLocalizedValues(content::WebUIDataSource* source) {
   }
 #endif
 
-  string16 tos = l10n_util::GetStringFUTF16(
+  base::string16 tos = l10n_util::GetStringFUTF16(
       IDS_ABOUT_TERMS_OF_SERVICE, UTF8ToUTF16(chrome::kChromeUITermsURL));
   source->AddString("productTOS", tos);
 
@@ -332,7 +332,7 @@ void HelpHandler::OnPageLoaded(const ListValue* args) {
       base::FundamentalValue(CanChangeChannel()));
 
   base::Time build_time = base::SysInfo::GetLsbReleaseTime();
-  string16 build_date = base::TimeFormatFriendlyDate(build_time);
+  base::string16 build_date = base::TimeFormatFriendlyDate(build_time);
   web_ui()->CallJavascriptFunction("help.HelpPage.setBuildDate",
                                    base::StringValue(build_date));
 #endif  // defined(OS_CHROMEOS)
@@ -427,7 +427,7 @@ void HelpHandler::RelaunchAndPowerwash(const ListValue* args) {
 #endif  // defined(OS_CHROMEOS)
 
 void HelpHandler::SetUpdateStatus(VersionUpdater::Status status,
-                                  int progress, const string16& message) {
+                                  int progress, const base::string16& message) {
   // Only UPDATING state should have progress set.
   DCHECK(status == VersionUpdater::UPDATING || progress == 0);
 
@@ -467,7 +467,7 @@ void HelpHandler::SetUpdateStatus(VersionUpdater::Status status,
 #if defined(OS_CHROMEOS)
   if (status == VersionUpdater::FAILED_OFFLINE ||
       status == VersionUpdater::FAILED_CONNECTION_TYPE_DISALLOWED) {
-    string16 types_msg = GetAllowedConnectionTypesMessage();
+    base::string16 types_msg = GetAllowedConnectionTypesMessage();
     if (!types_msg.empty()) {
       web_ui()->CallJavascriptFunction(
           "help.HelpPage.setAndShowAllowedConnectionTypesMsg",
diff --git a/chrome/browser/ui/webui/help/help_handler.h b/chrome/browser/ui/webui/help/help_handler.h
index 4131eb0..206f535 100644
--- a/chrome/browser/ui/webui/help/help_handler.h
+++ b/chrome/browser/ui/webui/help/help_handler.h
@@ -68,7 +68,7 @@ class HelpHandler : public content::WebUIMessageHandler,
 
   // Callback method which forwards status updates to the page.
   void SetUpdateStatus(VersionUpdater::Status status, int progress,
-                       const string16& fail_message);
+                       const base::string16& fail_message);
 
 #if defined(OS_MACOSX)
   // Callback method which forwards promotion state to the page.
diff --git a/chrome/browser/ui/webui/help/help_utils_chromeos.cc b/chrome/browser/ui/webui/help/help_utils_chromeos.cc
index 3cd29f1..8b30a39 100644
--- a/chrome/browser/ui/webui/help/help_utils_chromeos.cc
+++ b/chrome/browser/ui/webui/help/help_utils_chromeos.cc
@@ -61,7 +61,7 @@ string16 GetConnectionTypeAsUTF16(const std::string& type) {
   if (type == shill::kTypeVPN)
     return l10n_util::GetStringUTF16(IDS_NETWORK_TYPE_VPN);
   NOTREACHED();
-  return string16();
+  return base::string16();
 }
 
 }  // namespace help_utils_chromeos
diff --git a/chrome/browser/ui/webui/help/version_updater.h b/chrome/browser/ui/webui/help/version_updater.h
index a78444d..190ada7 100644
--- a/chrome/browser/ui/webui/help/version_updater.h
+++ b/chrome/browser/ui/webui/help/version_updater.h
@@ -41,9 +41,9 @@ class VersionUpdater {
 #endif
 
   // Used to update the client of status changes. int parameter is the progress
-  // and should only be non-zero for the UPDATING state.  string16 parameter is
-  // a message explaining a failure.
-  typedef base::Callback<void(Status, int, const string16&)>
+  // and should only be non-zero for the UPDATING state.
+  // base::string16 parameter is a message explaining a failure.
+  typedef base::Callback<void(Status, int, const base::string16&)>
       StatusCallback;
 
 #if defined(OS_MACOSX)
diff --git a/chrome/browser/ui/webui/help/version_updater_basic.cc b/chrome/browser/ui/webui/help/version_updater_basic.cc
index cb702aa..c0d0ee9 100644
--- a/chrome/browser/ui/webui/help/version_updater_basic.cc
+++ b/chrome/browser/ui/webui/help/version_updater_basic.cc
@@ -11,9 +11,9 @@
 void VersionUpdaterBasic::CheckForUpdate(
     const StatusCallback& status_callback) {
   if (UpgradeDetector::GetInstance()->notify_upgrade())
-    status_callback.Run(NEARLY_UPDATED, 0, string16());
+    status_callback.Run(NEARLY_UPDATED, 0, base::string16());
   else
-    status_callback.Run(DISABLED, 0, string16());
+    status_callback.Run(DISABLED, 0, base::string16());
 }
 
 void VersionUpdaterBasic::RelaunchBrowser() const {
diff --git a/chrome/browser/ui/webui/help/version_updater_chromeos.cc b/chrome/browser/ui/webui/help/version_updater_chromeos.cc
index b1362dd..74a475e 100644
--- a/chrome/browser/ui/webui/help/version_updater_chromeos.cc
+++ b/chrome/browser/ui/webui/help/version_updater_chromeos.cc
@@ -102,7 +102,7 @@ void VersionUpdaterCros::CheckForUpdate(const StatusCallback& callback) {
                   l10n_util::GetStringUTF16(IDS_UPGRADE_OFFLINE));
     return;
   } else if (status == NETWORK_STATUS_DISALLOWED) {
-    string16 message =
+    base::string16 message =
         l10n_util::GetStringFUTF16(
             IDS_UPGRADE_DISALLOWED,
             help_utils_chromeos::GetConnectionTypeAsUTF16(network->type()));
@@ -161,7 +161,7 @@ void VersionUpdaterCros::UpdateStatusChanged(
     const UpdateEngineClient::Status& status) {
   Status my_status = UPDATED;
   int progress = 0;
-  string16 message;
+  base::string16 message;
 
   // If the updater is currently idle, just show the last operation (unless it
   // was previously checking for an update -- in that case, the system is
@@ -213,5 +213,5 @@ void VersionUpdaterCros::OnUpdateCheck(
   // If version updating is not implemented, this binary is the most up-to-date
   // possible with respect to automatic updating.
   if (result == UpdateEngineClient::UPDATE_RESULT_NOTIMPLEMENTED)
-    callback_.Run(UPDATED, 0, string16());
+    callback_.Run(UPDATED, 0, base::string16());
 }
diff --git a/chrome/browser/ui/webui/help/version_updater_mac.mm b/chrome/browser/ui/webui/help/version_updater_mac.mm
index 331fe57..6b25716 100644
--- a/chrome/browser/ui/webui/help/version_updater_mac.mm
+++ b/chrome/browser/ui/webui/help/version_updater_mac.mm
@@ -102,7 +102,7 @@ void VersionUpdaterMac::CheckForUpdate(
   } else {
     // There is no glue, or the application is on a read-only filesystem.
     // Updates and promotions are impossible.
-    status_callback_.Run(DISABLED, 0, string16());
+    status_callback_.Run(DISABLED, 0, base::string16());
   }
 }
 
@@ -132,7 +132,7 @@ void VersionUpdaterMac::UpdateStatus(NSDictionary* dictionary) {
       [[dictionary objectForKey:kAutoupdateStatusStatus] intValue]);
 
   bool enable_promote_button = true;
-  string16 message;
+  base::string16 message;
 
   Status status;
   switch (keystone_status) {
@@ -198,9 +198,10 @@ void VersionUpdaterMac::UpdateStatus(NSDictionary* dictionary) {
     case kAutoupdateNeedsPromotion:
       {
         status = FAILED;
-        string16 product_name = l10n_util::GetStringUTF16(IDS_PRODUCT_NAME);
-        message = l10n_util:: GetStringFUTF16(IDS_PROMOTE_INFOBAR_TEXT,
-                                              product_name);
+        base::string16 product_name =
+            l10n_util::GetStringUTF16(IDS_PRODUCT_NAME);
+        message = l10n_util::GetStringFUTF16(IDS_PROMOTE_INFOBAR_TEXT,
+                                             product_name);
       }
       break;
 
diff --git a/chrome/browser/ui/webui/help/version_updater_win.cc b/chrome/browser/ui/webui/help/version_updater_win.cc
index 3d1a7ad..9491e10 100644
--- a/chrome/browser/ui/webui/help/version_updater_win.cc
+++ b/chrome/browser/ui/webui/help/version_updater_win.cc
@@ -47,13 +47,13 @@ class VersionUpdaterWin : public VersionUpdater,
   // GoogleUpdateStatusListener implementation.
   virtual void OnReportResults(GoogleUpdateUpgradeResult result,
                                GoogleUpdateErrorCode error_code,
-                               const string16& error_message,
-                               const string16& version) OVERRIDE;
+                               const base::string16& error_message,
+                               const base::string16& version) OVERRIDE;
 
   // Update the UI to show the status of the upgrade.
   void UpdateStatus(GoogleUpdateUpgradeResult result,
                     GoogleUpdateErrorCode error_code,
-                    const string16& error_message);
+                    const base::string16& error_message);
 
   // Got the intalled version so the handling of the UPGRADE_ALREADY_UP_TO_DATE
   // result case can now be completeb on the UI thread.
@@ -147,7 +147,8 @@ void VersionUpdaterWin::CheckForUpdate(const StatusCallback& callback) {
     // This could happen if the page got refreshed after results were returned.
     if (!google_updater_)
       CreateGoogleUpdater();
-    UpdateStatus(UPGRADE_CHECK_STARTED, GOOGLE_UPDATE_NO_ERROR, string16());
+    UpdateStatus(UPGRADE_CHECK_STARTED, GOOGLE_UPDATE_NO_ERROR,
+                 base::string16());
     // Specify false to not upgrade yet.
     google_updater_->CheckForUpdate(false, GetElevationParent());
   }
@@ -159,7 +160,7 @@ void VersionUpdaterWin::RelaunchBrowser() const {
 
 void VersionUpdaterWin::OnReportResults(
     GoogleUpdateUpgradeResult result, GoogleUpdateErrorCode error_code,
-    const string16& error_message, const string16& version) {
+    const base::string16& error_message, const base::string16& version) {
   // Drop the last reference to the object so that it gets cleaned up here.
   ClearGoogleUpdater();
   UpdateStatus(result, error_code, error_message);
@@ -167,13 +168,13 @@ void VersionUpdaterWin::OnReportResults(
 
 void VersionUpdaterWin::UpdateStatus(GoogleUpdateUpgradeResult result,
                                      GoogleUpdateErrorCode error_code,
-                                     const string16& error_message) {
+                                     const base::string16& error_message) {
   // For Chromium builds it would show an error message.
   // But it looks weird because in fact there is no error,
   // just the update server is not available for non-official builds.
 #if defined(GOOGLE_CHROME_BUILD)
   Status status = UPDATED;
-  string16 message;
+  base::string16 message;
 
   switch (result) {
     case UPGRADE_CHECK_STARTED: {
@@ -191,7 +192,7 @@ void VersionUpdaterWin::UpdateStatus(GoogleUpdateUpgradeResult result,
           UserMetricsAction("UpgradeCheck_UpgradeIsAvailable"));
       DCHECK(!google_updater_);  // Should have been nulled out already.
       CreateGoogleUpdater();
-      UpdateStatus(UPGRADE_STARTED, GOOGLE_UPDATE_NO_ERROR, string16());
+      UpdateStatus(UPGRADE_STARTED, GOOGLE_UPDATE_NO_ERROR, base::string16());
       // Specify true to upgrade now.
       google_updater_->CheckForUpdate(true, GetElevationParent());
       return;
@@ -255,10 +256,10 @@ void VersionUpdaterWin::GotInstalledVersion(const Version& version) {
   if (!version.IsValid() || version.CompareTo(running_version) <= 0) {
     content::RecordAction(
         UserMetricsAction("UpgradeCheck_AlreadyUpToDate"));
-    callback_.Run(UPDATED, 0, string16());
+    callback_.Run(UPDATED, 0, base::string16());
   } else {
     content::RecordAction(UserMetricsAction("UpgradeCheck_AlreadyUpgraded"));
-    callback_.Run(NEARLY_UPDATED, 0, string16());
+    callback_.Run(NEARLY_UPDATED, 0, base::string16());
   }
 }
 
diff --git a/chrome/browser/ui/webui/history_ui.cc b/chrome/browser/ui/webui/history_ui.cc
index 1d5c83c..50f80f8 100644
--- a/chrome/browser/ui/webui/history_ui.cc
+++ b/chrome/browser/ui/webui/history_ui.cc
@@ -195,7 +195,7 @@ content::WebUIDataSource* CreateHistoryUIHTMLSource(Profile* profile) {
 // indicator (e.g. today, yesterday).
 string16 getRelativeDateLocalized(const base::Time& visit_time) {
   base::Time midnight = base::Time::Now().LocalMidnight();
-  string16 date_str = ui::TimeFormat::RelativeDate(visit_time, &midnight);
+  base::string16 date_str = ui::TimeFormat::RelativeDate(visit_time, &midnight);
   if (date_str.empty()) {
     date_str = base::TimeFormatFriendlyDate(visit_time);
   } else {
@@ -263,9 +263,9 @@ void GetDeviceNameAndType(const ProfileSyncService* sync_service,
 
 BrowsingHistoryHandler::HistoryEntry::HistoryEntry(
     BrowsingHistoryHandler::HistoryEntry::EntryType entry_type,
-    const GURL& url, const string16& title, base::Time time,
+    const GURL& url, const base::string16& title, base::Time time,
     const std::string& client_id, bool is_search_result,
-    const string16& snippet, bool blocked_visit,
+    const base::string16& snippet, bool blocked_visit,
     const std::string& accept_languages) {
   this->entry_type = entry_type;
   this->url = url;
@@ -291,7 +291,7 @@ void BrowsingHistoryHandler::HistoryEntry::SetUrlAndTitle(
   result->SetString("url", url.spec());
 
   bool using_url_as_the_title = false;
-  string16 title_to_set(title);
+  base::string16 title_to_set(title);
   if (title.empty()) {
     using_url_as_the_title = true;
     title_to_set = UTF8ToUTF16(url.spec());
@@ -338,7 +338,7 @@ scoped_ptr<DictionaryValue> BrowsingHistoryHandler::HistoryEntry::ToValue(
     result->SetString("snippet", snippet);
   } else {
     base::Time midnight = base::Time::Now().LocalMidnight();
-    string16 date_str = ui::TimeFormat::RelativeDate(time, &midnight);
+    base::string16 date_str = ui::TimeFormat::RelativeDate(time, &midnight);
     if (date_str.empty()) {
       date_str = base::TimeFormatFriendlyDate(time);
     } else {
@@ -434,7 +434,7 @@ void BrowsingHistoryHandler::WebHistoryTimeout() {
 }
 
 void BrowsingHistoryHandler::QueryHistory(
-    string16 search_text, const history::QueryOptions& options) {
+    base::string16 search_text, const history::QueryOptions& options) {
   Profile* profile = Profile::FromWebUI(web_ui());
 
   // Anything in-flight is invalid.
@@ -486,7 +486,7 @@ void BrowsingHistoryHandler::HandleQueryHistory(const ListValue* args) {
   //   returned.
   // - the maximum number of results to return (may be 0, meaning that there
   //   is no maximum).
-  string16 search_text = ExtractStringValue(args);
+  base::string16 search_text = ExtractStringValue(args);
   int offset;
   if (!args->GetInteger(1, &offset)) {
     NOTREACHED() << "Failed to convert argument 1. ";
@@ -540,7 +540,7 @@ void BrowsingHistoryHandler::HandleRemoveVisits(const ListValue* args) {
   DCHECK(urls_to_be_deleted_.empty());
   for (ListValue::const_iterator it = args->begin(); it != args->end(); ++it) {
     DictionaryValue* deletion = NULL;
-    string16 url;
+    base::string16 url;
     ListValue* timestamps = NULL;
 
     // Each argument is a dictionary with properties "url" and "timestamps".
@@ -641,7 +641,7 @@ void BrowsingHistoryHandler::HandleClearBrowsingData(const ListValue* args) {
 }
 
 void BrowsingHistoryHandler::HandleRemoveBookmark(const ListValue* args) {
-  string16 url = ExtractStringValue(args);
+  base::string16 url = ExtractStringValue(args);
   Profile* profile = Profile::FromWebUI(web_ui());
   BookmarkModel* model = BookmarkModelFactory::GetForProfile(profile);
   bookmark_utils::RemoveAllBookmarks(model, GURL(url));
@@ -741,7 +741,7 @@ void BrowsingHistoryHandler::ReturnResultsToFrontEnd() {
 }
 
 void BrowsingHistoryHandler::QueryComplete(
-    const string16& search_text,
+    const base::string16& search_text,
     const history::QueryOptions& options,
     HistoryService::Handle request_handle,
     history::QueryResults* results) {
@@ -785,7 +785,7 @@ void BrowsingHistoryHandler::QueryComplete(
 }
 
 void BrowsingHistoryHandler::WebHistoryQueryComplete(
-    const string16& search_text,
+    const base::string16& search_text,
     const history::QueryOptions& options,
     base::TimeTicks start_time,
     history::WebHistoryService::Request* request,
@@ -814,8 +814,8 @@ void BrowsingHistoryHandler::WebHistoryQueryComplete(
       const DictionaryValue* result = NULL;
       const ListValue* results = NULL;
       const ListValue* ids = NULL;
-      string16 url;
-      string16 title;
+      base::string16 url;
+      base::string16 title;
       base::Time visit_time;
 
       if (!(events->GetDictionary(i, &event) &&
@@ -859,7 +859,7 @@ void BrowsingHistoryHandler::WebHistoryQueryComplete(
                 time,
                 client_id,
                 !search_text.empty(),
-                string16(),
+                base::string16(),
                 /* blocked_visit */ false,
                 accept_languages));
       }
@@ -993,7 +993,7 @@ HistoryUI::HistoryUI(content::WebUI* web_ui) : WebUIController(web_ui) {
 }
 
 // static
-const GURL HistoryUI::GetHistoryURLWithSearchText(const string16& text) {
+const GURL HistoryUI::GetHistoryURLWithSearchText(const base::string16& text) {
   return GURL(std::string(chrome::kChromeUIHistoryURL) + "#q=" +
               net::EscapeQueryParamValue(UTF16ToUTF8(text), true));
 }
diff --git a/chrome/browser/ui/webui/history_ui.h b/chrome/browser/ui/webui/history_ui.h
index 6c4177a..fc76fef 100644
--- a/chrome/browser/ui/webui/history_ui.h
+++ b/chrome/browser/ui/webui/history_ui.h
@@ -39,9 +39,9 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
       COMBINED_ENTRY
     };
 
-    HistoryEntry(EntryType type, const GURL& url, const string16& title,
+    HistoryEntry(EntryType type, const GURL& url, const base::string16& title,
                  base::Time time, const std::string& client_id,
-                 bool is_search_result, const string16& snippet,
+                 bool is_search_result, const base::string16& snippet,
                  bool blocked_visit, const std::string& accept_languages);
     HistoryEntry();
     virtual ~HistoryEntry();
@@ -63,7 +63,7 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
     EntryType entry_type;
 
     GURL url;
-    string16 title;  // Title of the entry. May be empty.
+    base::string16 title;  // Title of the entry. May be empty.
 
     // The time of the entry. Usually this will be the time of the most recent
     // visit to |url| on a particular day as defined in the local timezone.
@@ -79,7 +79,7 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
     bool is_search_result;
 
     // The entry's search snippet, if this entry is a search result.
-    string16 snippet;
+    base::string16 snippet;
 
     // Whether this entry was blocked when it was attempted.
     bool blocked_visit;
@@ -140,13 +140,13 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
   void WebHistoryTimeout();
 
   // Callback from the history system when a history query has completed.
-  void QueryComplete(const string16& search_text,
+  void QueryComplete(const base::string16& search_text,
                      const history::QueryOptions& options,
                      HistoryService::Handle request_handle,
                      history::QueryResults* results);
 
   // Callback from the WebHistoryService when a query has completed.
-  void WebHistoryQueryComplete(const string16& search_text,
+  void WebHistoryQueryComplete(const base::string16& search_text,
                                const history::QueryOptions& options,
                                base::TimeTicks start_time,
                                history::WebHistoryService::Request* request,
@@ -210,7 +210,7 @@ class HistoryUI : public content::WebUIController {
   explicit HistoryUI(content::WebUI* web_ui);
 
   // Return the URL for a given search term.
-  static const GURL GetHistoryURLWithSearchText(const string16& text);
+  static const GURL GetHistoryURLWithSearchText(const base::string16& text);
 
   static base::RefCountedMemory* GetFaviconResourceBytes(
       ui::ScaleFactor scale_factor);
diff --git a/chrome/browser/ui/webui/inline_login_ui.cc b/chrome/browser/ui/webui/inline_login_ui.cc
index 7652990..1b3822c 100644
--- a/chrome/browser/ui/webui/inline_login_ui.cc
+++ b/chrome/browser/ui/webui/inline_login_ui.cc
@@ -205,7 +205,7 @@ class InlineLoginUIHandler : public content::WebUIMessageHandler {
 
   // JS callback:
   void HandleSwitchToFullTab(const base::ListValue* args) {
-    string16 url_str;
+    base::string16 url_str;
     CHECK(args->GetString(0, &url_str));
 
     content::WebContents* web_contents = web_ui()->GetWebContents();
@@ -233,8 +233,8 @@ class InlineLoginUIHandler : public content::WebUIMessageHandler {
     oauth2_token_fetcher_->StartExchangeFromCookies();
 #else
     const base::DictionaryValue* dict = NULL;
-    string16 email;
-    string16 password;
+    base::string16 email;
+    base::string16 password;
     if (!args->GetDictionary(0, &dict) || !dict ||
         !dict->GetString("email", &email)) {
       NOTREACHED();
@@ -281,8 +281,8 @@ class InlineLoginUIHandler : public content::WebUIMessageHandler {
   }
 
   void OnGaiaCookiesFetched(
-      const string16 email,
-      const string16 password,
+      const base::string16 email,
+      const base::string16 password,
       const net::CookieList& cookie_list) {
     net::CookieList::const_iterator it;
     std::string oauth_code;
diff --git a/chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.cc b/chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.cc
index 21421df..cddc71b 100644
--- a/chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.cc
+++ b/chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.cc
@@ -597,7 +597,7 @@ void LocalDiscoveryUIHandler::SetupCloudPrintConnectorSection() {
   }
   base::FundamentalValue disabled(email.empty());
 
-  string16 label_str;
+  base::string16 label_str;
   if (email.empty()) {
     label_str = l10n_util::GetStringFUTF16(
         IDS_LOCAL_DISCOVERY_CLOUD_PRINT_CONNECTOR_DISABLED_LABEL,
diff --git a/chrome/browser/ui/webui/memory_internals/memory_internals_handler.cc b/chrome/browser/ui/webui/memory_internals/memory_internals_handler.cc
index 1cba471..00e0863 100644
--- a/chrome/browser/ui/webui/memory_internals/memory_internals_handler.cc
+++ b/chrome/browser/ui/webui/memory_internals/memory_internals_handler.cc
@@ -38,7 +38,7 @@ void MemoryInternalsHandler::OnJSUpdate(const base::ListValue* list) {
   proxy_->StartFetch(list);
 }
 
-void MemoryInternalsHandler::OnUpdate(const string16& update) {
+void MemoryInternalsHandler::OnUpdate(const base::string16& update) {
   // Don't try to execute JavaScript in a RenderView that no longer exists.
   content::RenderViewHost* host =
       web_ui()->GetWebContents()->GetRenderViewHost();
diff --git a/chrome/browser/ui/webui/memory_internals/memory_internals_handler.h b/chrome/browser/ui/webui/memory_internals/memory_internals_handler.h
index 8cc9ce0..78ba377 100644
--- a/chrome/browser/ui/webui/memory_internals/memory_internals_handler.h
+++ b/chrome/browser/ui/webui/memory_internals/memory_internals_handler.h
@@ -30,7 +30,7 @@ class MemoryInternalsHandler : public content::WebUIMessageHandler {
   void OnJSUpdate(const base::ListValue* list);
 
   // MemoryInternals message handlers.
-  void OnUpdate(const string16& update);
+  void OnUpdate(const base::string16& update);
 
  private:
   scoped_refptr<MemoryInternalsProxy> proxy_;
diff --git a/chrome/browser/ui/webui/memory_internals/memory_internals_proxy.cc b/chrome/browser/ui/webui/memory_internals/memory_internals_proxy.cc
index 2e549f0..4c465ee 100644
--- a/chrome/browser/ui/webui/memory_internals/memory_internals_proxy.cc
+++ b/chrome/browser/ui/webui/memory_internals/memory_internals_proxy.cc
@@ -353,7 +353,8 @@ void MemoryInternalsProxy::CallJavaScriptFunctionOnUIThread(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   std::vector<const base::Value*> args_vector(1, &args);
-  string16 update = content::WebUI::GetJavascriptCall(function, args_vector);
+  base::string16 update =
+      content::WebUI::GetJavascriptCall(function, args_vector);
   // Don't forward updates to a destructed UI.
   if (handler_)
     handler_->OnUpdate(update);
diff --git a/chrome/browser/ui/webui/nacl_ui.cc b/chrome/browser/ui/webui/nacl_ui.cc
index de7e26e..7408325 100644
--- a/chrome/browser/ui/webui/nacl_ui.cc
+++ b/chrome/browser/ui/webui/nacl_ui.cc
@@ -154,7 +154,9 @@ void NaClDomHandler::RegisterMessages() {
 
 // Helper functions for collecting a list of key-value pairs that will
 // be displayed.
-void AddPair(ListValue* list, const string16& key, const string16& value) {
+void AddPair(ListValue* list,
+             const base::string16& key,
+             const base::string16& value) {
   DictionaryValue* results = new DictionaryValue();
   results->SetString("key", key);
   results->SetString("value", value);
@@ -217,8 +219,8 @@ void NaClDomHandler::AddPluginList(ListValue* list) {
   std::vector<content::WebPluginInfo> info_array;
   PluginService::GetInstance()->GetPluginInfoArray(
       GURL(), "application/x-nacl", false, &info_array, NULL);
-  string16 nacl_version;
-  string16 nacl_key = ASCIIToUTF16("NaCl plugin");
+  base::string16 nacl_version;
+  base::string16 nacl_key = ASCIIToUTF16("NaCl plugin");
   if (info_array.empty()) {
     AddPair(list, nacl_key, ASCIIToUTF16("Disabled"));
   } else {
@@ -247,7 +249,7 @@ void NaClDomHandler::AddPluginList(ListValue* list) {
 
 void NaClDomHandler::AddPnaclInfo(ListValue* list) {
   // Display whether PNaCl is enabled.
-  string16 pnacl_enabled_string = ASCIIToUTF16("Enabled");
+  base::string16 pnacl_enabled_string = ASCIIToUTF16("Enabled");
   if (!isPluginEnabled(0)) {
     pnacl_enabled_string = ASCIIToUTF16("Disabled in profile prefs");
   } else if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -277,7 +279,7 @@ void NaClDomHandler::AddPnaclInfo(ListValue* list) {
 }
 
 void NaClDomHandler::AddNaClInfo(ListValue* list) {
-  string16 nacl_enabled_string = ASCIIToUTF16("Disabled");
+  base::string16 nacl_enabled_string = ASCIIToUTF16("Disabled");
   if (isPluginEnabled(0) &&
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableNaCl)) {
     nacl_enabled_string = ASCIIToUTF16("Enabled by flag '--enable-nacl'");
diff --git a/chrome/browser/ui/webui/net_internals/net_internals_ui.cc b/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
index 2f40b4d..fdceb4e 100644
--- a/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
+++ b/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
@@ -1187,7 +1187,7 @@ void NetInternalsMessageHandler::IOThreadImpl::OnEnableIPv6(
 void NetInternalsMessageHandler::IOThreadImpl::OnStartConnectionTests(
     const ListValue* list) {
   // |value| should be: [<URL to test>].
-  string16 url_str;
+  base::string16 url_str;
   CHECK(list->GetString(0, &url_str));
 
   // Try to fix-up the user provided URL into something valid.
diff --git a/chrome/browser/ui/webui/ntp/android/context_menu_handler.cc b/chrome/browser/ui/webui/ntp/android/context_menu_handler.cc
index 7c916f4..328be22 100644
--- a/chrome/browser/ui/webui/ntp/android/context_menu_handler.cc
+++ b/chrome/browser/ui/webui/ntp/android/context_menu_handler.cc
@@ -126,7 +126,7 @@ void ContextMenuHandler::HandleOpenInIncognitoTab(const ListValue* args) {
 
 void ContextMenuHandler::OpenUrl(const ListValue* args,
                                  WindowOpenDisposition disposition) {
-  string16 url = ExtractStringValue(args);
+  base::string16 url = ExtractStringValue(args);
   if (!url.empty()) {
     web_ui()->GetWebContents()->OpenURL(content::OpenURLParams(
         GURL(url), content::Referrer(), disposition,
diff --git a/chrome/browser/ui/webui/ntp/android/ntp_resource_cache_android.cc b/chrome/browser/ui/webui/ntp/android/ntp_resource_cache_android.cc
index 29b8cd8..0b09b2d 100644
--- a/chrome/browser/ui/webui/ntp/android/ntp_resource_cache_android.cc
+++ b/chrome/browser/ui/webui/ntp/android/ntp_resource_cache_android.cc
@@ -149,7 +149,7 @@ void NTPResourceCache::CreateNewTabHTML() {
       bookmark_shortcuts_allowed ? "true" : "false");
 
   const char* new_tab_link = kLearnMoreIncognitoUrl;
-  string16 learnMoreLink = ASCIIToUTF16(
+  base::string16 learnMoreLink = ASCIIToUTF16(
       google_util::AppendGoogleLocaleParam(GURL(new_tab_link)).spec());
   localized_strings.SetString("content",
       l10n_util::GetStringFUTF16(
diff --git a/chrome/browser/ui/webui/ntp/android/promo_handler.cc b/chrome/browser/ui/webui/ntp/android/promo_handler.cc
index b3a1663..fc43d70 100644
--- a/chrome/browser/ui/webui/ntp/android/promo_handler.cc
+++ b/chrome/browser/ui/webui/ntp/android/promo_handler.cc
@@ -152,7 +152,7 @@ void PromoHandler::HandlePromoSendEmail(const base::ListValue* args) {
   if (!profile)
     return;
 
-  string16 data_subject, data_body, data_inv;
+  base::string16 data_subject, data_body, data_inv;
   if (!args || args->GetSize() < 3) {
     DVLOG(1) << "promoSendEmail: expected three args, got "
              << (args ? args->GetSize() : 0);
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
index 0d6383a..e35efca 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
@@ -114,14 +114,14 @@ void AppLauncherHandler::CreateAppInfo(
 
   // The Extension class 'helpfully' wraps bidi control characters that
   // impede our ability to determine directionality.
-  string16 short_name = UTF8ToUTF16(extension->short_name());
+  base::string16 short_name = UTF8ToUTF16(extension->short_name());
   base::i18n::UnadjustStringForLocaleDirection(&short_name);
   NewTabUI::SetUrlTitleAndDirection(
       value,
       short_name,
       extensions::AppLaunchInfo::GetFullLaunchURL(extension));
 
-  string16 name = UTF8ToUTF16(extension->name());
+  base::string16 name = UTF8ToUTF16(extension->name());
   base::i18n::UnadjustStringForLocaleDirection(&name);
   NewTabUI::SetFullNameAndDirection(name, value);
 
@@ -657,7 +657,7 @@ void AppLauncherHandler::HandleSetPageIndex(const ListValue* args) {
 }
 
 void AppLauncherHandler::HandleSaveAppPageName(const ListValue* args) {
-  string16 name;
+  base::string16 name;
   CHECK(args->GetString(0, &name));
 
   double page_index;
@@ -675,7 +675,7 @@ void AppLauncherHandler::HandleGenerateAppForLink(const ListValue* args) {
   CHECK(args->GetString(0, &url));
   GURL launch_url(url);
 
-  string16 title;
+  base::string16 title;
   CHECK(args->GetString(1, &title));
 
   double page_index;
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.h b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
index 411779a..a3547bb 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.h
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
@@ -112,7 +112,7 @@ class AppLauncherHandler : public content::WebUIMessageHandler,
     ~AppInstallInfo();
 
     bool is_bookmark_app;
-    string16 title;
+    base::string16 title;
     GURL app_url;
     syncer::StringOrdinal page_ordinal;
   };
diff --git a/chrome/browser/ui/webui/ntp/foreign_session_handler.h b/chrome/browser/ui/webui/ntp/foreign_session_handler.h
index 443f124..477061a 100644
--- a/chrome/browser/ui/webui/ntp/foreign_session_handler.h
+++ b/chrome/browser/ui/webui/ntp/foreign_session_handler.h
@@ -65,7 +65,7 @@ class ForeignSessionHandler : public content::WebUIMessageHandler,
   bool IsTabSyncEnabled();
 
   // Returns a string used to show the user when a session was last modified.
-  string16 FormatSessionTime(const base::Time& time);
+  base::string16 FormatSessionTime(const base::Time& time);
 
   // Determines which session is to be opened, and then calls
   // OpenForeignSession, to begin the process of opening a new browser window.
diff --git a/chrome/browser/ui/webui/ntp/new_tab_page_sync_handler.cc b/chrome/browser/ui/webui/ntp/new_tab_page_sync_handler.cc
index 74ab381..53dad5c 100644
--- a/chrome/browser/ui/webui/ntp/new_tab_page_sync_handler.cc
+++ b/chrome/browser/ui/webui/ntp/new_tab_page_sync_handler.cc
@@ -111,8 +111,8 @@ void NewTabPageSyncHandler::BuildAndSendSyncStatus() {
   // "Sync error", when we can't authenticate or establish a connection with
   //               the sync server (appropriate information appended to
   //               message).
-  string16 status_msg;
-  string16 link_text;
+  base::string16 status_msg;
+  base::string16 link_text;
 
   sync_ui_util::MessageType type =
       sync_ui_util::GetStatusLabelsForNewTabPage(sync_service_,
@@ -134,7 +134,7 @@ void NewTabPageSyncHandler::HandleSyncLinkClicked(const ListValue* args) {
   chrome::ShowBrowserSignin(browser, signin::SOURCE_NTP_LINK);
 
   if (sync_service_->HasSyncSetupCompleted()) {
-    string16 user = UTF8ToUTF16(SigninManagerFactory::GetForProfile(
+    base::string16 user = UTF8ToUTF16(SigninManagerFactory::GetForProfile(
         Profile::FromWebUI(web_ui()))->GetAuthenticatedUsername());
     DictionaryValue value;
     value.SetString("syncEnabledMessage",
diff --git a/chrome/browser/ui/webui/ntp/new_tab_ui.cc b/chrome/browser/ui/webui/ntp/new_tab_ui.cc
index 8d04ea5..36c9cd2 100644
--- a/chrome/browser/ui/webui/ntp/new_tab_ui.cc
+++ b/chrome/browser/ui/webui/ntp/new_tab_ui.cc
@@ -76,7 +76,7 @@ const char kLTRHtmlTextDirection[] = "ltr";
 
 static base::LazyInstance<std::set<const WebUIController*> > g_live_new_tabs;
 
-const char* GetHtmlTextDirection(const string16& text) {
+const char* GetHtmlTextDirection(const base::string16& text) {
   if (base::i18n::IsRTL() && base::i18n::StringContainsStrongRTLChars(text))
     return kRTLHtmlTextDirection;
   else
@@ -294,12 +294,12 @@ bool NewTabUI::IsDiscoveryInNTPEnabled() {
 
 // static
 void NewTabUI::SetUrlTitleAndDirection(DictionaryValue* dictionary,
-                                       const string16& title,
+                                       const base::string16& title,
                                        const GURL& gurl) {
   dictionary->SetString("url", gurl.spec());
 
   bool using_url_as_the_title = false;
-  string16 title_to_set(title);
+  base::string16 title_to_set(title);
   if (title_to_set.empty()) {
     using_url_as_the_title = true;
     title_to_set = UTF8ToUTF16(gurl.spec());
@@ -327,7 +327,7 @@ void NewTabUI::SetUrlTitleAndDirection(DictionaryValue* dictionary,
 }
 
 // static
-void NewTabUI::SetFullNameAndDirection(const string16& full_name,
+void NewTabUI::SetFullNameAndDirection(const base::string16& full_name,
                                        base::DictionaryValue* dictionary) {
   dictionary->SetString("full_name", full_name);
   dictionary->SetString("full_name_direction", GetHtmlTextDirection(full_name));
diff --git a/chrome/browser/ui/webui/ntp/new_tab_ui.h b/chrome/browser/ui/webui/ntp/new_tab_ui.h
index 490085a2..b28775a 100644
--- a/chrome/browser/ui/webui/ntp/new_tab_ui.h
+++ b/chrome/browser/ui/webui/ntp/new_tab_ui.h
@@ -56,11 +56,11 @@ class NewTabUI : public content::WebUIController,
   // Adds "url", "title", and "direction" keys on incoming dictionary, setting
   // title as the url as a fallback on empty title.
   static void SetUrlTitleAndDirection(base::DictionaryValue* dictionary,
-                                      const string16& title,
+                                      const base::string16& title,
                                       const GURL& gurl);
 
   // Adds "full_name" and "full_name_direction" keys on incoming dictionary.
-  static void SetFullNameAndDirection(const string16& full_name,
+  static void SetFullNameAndDirection(const base::string16& full_name,
                                       base::DictionaryValue* dictionary);
 
   // Returns a pointer to a NewTabUI if the WebUIController object is a new tab
diff --git a/chrome/browser/ui/webui/ntp/ntp_login_handler.cc b/chrome/browser/ui/webui/ntp/ntp_login_handler.cc
index 35a31b0..0185258 100644
--- a/chrome/browser/ui/webui/ntp/ntp_login_handler.cc
+++ b/chrome/browser/ui/webui/ntp/ntp_login_handler.cc
@@ -69,7 +69,7 @@ SkBitmap GetGAIAPictureForNTP(const gfx::Image& image) {
 }
 
 // Puts the |content| into a span with the given CSS class.
-string16 CreateSpanWithClass(const string16& content,
+string16 CreateSpanWithClass(const base::string16& content,
                              const std::string& css_class) {
   return ASCIIToUTF16("<span class='" + css_class + "'>") +
       net::EscapeForHTML(content) + ASCIIToUTF16("</span>");
@@ -201,7 +201,7 @@ void NTPLoginHandler::UpdateLogin() {
   std::string username = profile->GetPrefs()->GetString(
       prefs::kGoogleServicesUsername);
 
-  string16 header, sub_header;
+  base::string16 header, sub_header;
   std::string icon_url;
   if (!username.empty()) {
     ProfileInfoCache& cache =
@@ -212,7 +212,7 @@ void NTPLoginHandler::UpdateLogin() {
       // case. In the multi-profile case the profile picture is visible in the
       // title bar and the full name can be ambiguous.
       if (cache.GetNumberOfProfiles() == 1) {
-        string16 name = cache.GetGAIANameOfProfileAtIndex(profile_index);
+        base::string16 name = cache.GetGAIANameOfProfileAtIndex(profile_index);
         if (!name.empty())
           header = CreateSpanWithClass(name, "profile-name");
         const gfx::Image* image =
@@ -233,7 +233,7 @@ void NTPLoginHandler::UpdateLogin() {
     SigninManager* signin = SigninManagerFactory::GetForProfile(
         profile->GetOriginalProfile());
     if (!profile->IsManaged() && signin->IsSigninAllowed()) {
-      string16 signed_in_link = l10n_util::GetStringUTF16(
+      base::string16 signed_in_link = l10n_util::GetStringUTF16(
           IDS_SYNC_PROMO_NOT_SIGNED_IN_STATUS_LINK);
       signed_in_link = CreateSpanWithClass(signed_in_link, "link-span");
       header = l10n_util::GetStringFUTF16(
@@ -273,7 +273,7 @@ void NTPLoginHandler::GetLocalizedValues(Profile* profile,
   PrefService* prefs = profile->GetPrefs();
   bool hide_sync = !prefs->GetBoolean(prefs::kSignInPromoShowNTPBubble);
 
-  string16 message = hide_sync ? string16() :
+  base::string16 message = hide_sync ? base::string16() :
       l10n_util::GetStringFUTF16(IDS_SYNC_PROMO_NTP_BUBBLE_MESSAGE,
           l10n_util::GetStringUTF16(IDS_SHORT_PRODUCT_NAME));
 
@@ -281,9 +281,9 @@ void NTPLoginHandler::GetLocalizedValues(Profile* profile,
   values->SetString("login_status_url",
       hide_sync ? std::string() : chrome::kSyncLearnMoreURL);
   values->SetString("login_status_advanced",
-      hide_sync ? string16() :
+      hide_sync ? base::string16() :
       l10n_util::GetStringUTF16(IDS_SYNC_PROMO_NTP_BUBBLE_ADVANCED));
   values->SetString("login_status_dismiss",
-      hide_sync ? string16() :
+      hide_sync ? base::string16() :
       l10n_util::GetStringUTF16(IDS_SYNC_PROMO_NTP_BUBBLE_OK));
 }
diff --git a/chrome/browser/ui/webui/ntp/ntp_resource_cache.cc b/chrome/browser/ui/webui/ntp/ntp_resource_cache.cc
index a62fe18..73a05ed 100644
--- a/chrome/browser/ui/webui/ntp/ntp_resource_cache.cc
+++ b/chrome/browser/ui/webui/ntp/ntp_resource_cache.cc
@@ -309,7 +309,7 @@ void NTPResourceCache::CreateNewTabIncognitoHTML() {
     if (!enterprise_domain.empty()) {
       // Device is enterprise enrolled.
       localized_strings.SetString("enterpriseInfoVisible", "true");
-      string16 enterprise_info = l10n_util::GetStringFUTF16(
+      base::string16 enterprise_info = l10n_util::GetStringFUTF16(
           IDS_DEVICE_OWNED_BY_NOTICE,
           UTF8ToUTF16(enterprise_domain));
       localized_strings.SetString("enterpriseInfoMessage", enterprise_info);
diff --git a/chrome/browser/ui/webui/ntp/ntp_resource_cache.h b/chrome/browser/ui/webui/ntp/ntp_resource_cache.h
index a5203e1..cc76dd2 100644
--- a/chrome/browser/ui/webui/ntp/ntp_resource_cache.h
+++ b/chrome/browser/ui/webui/ntp/ntp_resource_cache.h
@@ -79,7 +79,7 @@ class NTPResourceCache : public content::NotificationObserver,
 #if !defined(OS_ANDROID)
   // Returns a message describing any newly-added sync types, or an empty
   // string if all types have already been acknowledged.
-  string16 GetSyncTypeMessage();
+  base::string16 GetSyncTypeMessage();
 
   void CreateNewTabIncognitoHTML();
   void CreateNewTabIncognitoCSS();
diff --git a/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.cc b/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.cc
index ac24b5b..6e35ec3 100644
--- a/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.cc
+++ b/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.cc
@@ -80,7 +80,7 @@ void OmniboxUIHandler::OnResultChanged(bool default_match_changed) {
   result_to_output.SetBoolean("done", controller_->done());
   result_to_output.SetInteger("time_since_omnibox_started_ms",
       (base::Time::Now() - time_omnibox_started_).InMilliseconds());
-  const string16& host = controller_->input().text().substr(
+  const base::string16& host = controller_->input().text().substr(
       controller_->input().parts().host.begin,
       controller_->input().parts().host.len);
   result_to_output.SetString("host", host);
@@ -158,7 +158,7 @@ void OmniboxUIHandler::AddResultToDictionary(const std::string& prefix,
   output->SetInteger(prefix + ".num_items", i);
 }
 
-bool OmniboxUIHandler::LookupIsTypedHost(const string16& host,
+bool OmniboxUIHandler::LookupIsTypedHost(const base::string16& host,
                                          bool* is_typed_host) const {
   HistoryService* const history_service =
       HistoryServiceFactory::GetForProfile(profile_,
@@ -174,7 +174,7 @@ bool OmniboxUIHandler::LookupIsTypedHost(const string16& host,
 
 void OmniboxUIHandler::StartOmniboxQuery(const base::ListValue* input) {
   DCHECK_EQ(4u, input->GetSize());
-  string16 input_string;
+  base::string16 input_string;
   bool return_val = input->GetString(0, &input_string);
   DCHECK(return_val);
   int cursor_position;
@@ -196,7 +196,7 @@ void OmniboxUIHandler::StartOmniboxQuery(const base::ListValue* input) {
   controller_->Start(AutocompleteInput(
       input_string,
       cursor_position,
-      string16(),  // user's desired tld (top-level domain)
+      base::string16(),  // user's desired tld (top-level domain)
       GURL(),
       AutocompleteInput::INVALID_SPEC,
       prevent_inline_autocomplete,
diff --git a/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.h b/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.h
index 8c18792..f19cbb4 100644
--- a/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.h
+++ b/chrome/browser/ui/webui/omnibox/omnibox_ui_handler.h
@@ -68,7 +68,7 @@ class OmniboxUIHandler : public AutocompleteControllerDelegate,
   // Looks up whether the hostname is a typed host (i.e., has received
   // typed visits).  Return true if the lookup succeeded; if so, the
   // value of |is_typed_host| is set appropriately.
-  bool LookupIsTypedHost(const string16& host, bool* is_typed_host) const;
+  bool LookupIsTypedHost(const base::string16& host, bool* is_typed_host) const;
 
   // Re-initializes the AutocompleteController in preparation for the
   // next query.
diff --git a/chrome/browser/ui/webui/options/autofill_options_handler.cc b/chrome/browser/ui/webui/options/autofill_options_handler.cc
index 3e52253..defae47 100644
--- a/chrome/browser/ui/webui/options/autofill_options_handler.cc
+++ b/chrome/browser/ui/webui/options/autofill_options_handler.cc
@@ -98,7 +98,7 @@ void SetValueList(const ListValue* list,
                   AutofillProfile* profile) {
   std::vector<string16> values(list->GetSize());
   for (size_t i = 0; i < list->GetSize(); ++i) {
-    string16 value;
+    base::string16 value;
     if (list->GetString(i, &value))
       values[i] = value;
   }
@@ -146,17 +146,17 @@ void SetNameList(const ListValue* names, AutofillProfile* profile) {
     bool success = names->GetList(i, &name);
     DCHECK(success);
 
-    string16 first_name;
+    base::string16 first_name;
     success = name->GetString(0, &first_name);
     DCHECK(success);
     first_names[i] = first_name;
 
-    string16 middle_name;
+    base::string16 middle_name;
     success = name->GetString(1, &middle_name);
     DCHECK(success);
     middle_names[i] = middle_name;
 
-    string16 last_name;
+    base::string16 last_name;
     success = name->GetString(2, &last_name);
     DCHECK(success);
     last_names[i] = last_name;
@@ -200,7 +200,7 @@ void ExtractPhoneNumberInformation(const ListValue* args,
 void RemoveDuplicatePhoneNumberAtIndex(size_t index,
                                        const std::string& country_code,
                                        ListValue* list) {
-  string16 new_value;
+  base::string16 new_value;
   if (!list->GetString(index, &new_value)) {
     NOTREACHED() << "List should have a value at index " << index;
     return;
@@ -212,7 +212,7 @@ void RemoveDuplicatePhoneNumberAtIndex(size_t index,
     if (i == index)
       continue;
 
-    string16 existing_value;
+    base::string16 existing_value;
     if (!list->GetString(i, &existing_value)) {
       NOTREACHED() << "List should have a value at index " << i;
       continue;
@@ -520,7 +520,7 @@ void AutofillOptionsHandler::SetAddress(const ListValue* args) {
   AutofillProfile profile(guid, kSettingsOrigin);
 
   std::string country_code;
-  string16 value;
+  base::string16 value;
   const ListValue* list_value;
   if (args->GetList(1, &list_value))
     SetNameList(list_value, &profile);
@@ -573,7 +573,7 @@ void AutofillOptionsHandler::SetCreditCard(const ListValue* args) {
 
   CreditCard credit_card(guid, kSettingsOrigin);
 
-  string16 value;
+  base::string16 value;
   if (args->GetString(1, &value))
     credit_card.SetRawInfo(autofill::CREDIT_CARD_NAME, value);
 
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.cc b/chrome/browser/ui/webui/options/browser_options_handler.cc
index b21e156..81d2fb48 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -470,7 +470,7 @@ void BrowserOptionsHandler::GetLocalizedValues(DictionaryValue* values) {
 #endif
 
   values->SetString("syncLearnMoreURL", chrome::kSyncLearnMoreURL);
-  string16 omnibox_url = ASCIIToUTF16(chrome::kOmniboxLearnMoreURL);
+  base::string16 omnibox_url = ASCIIToUTF16(chrome::kOmniboxLearnMoreURL);
   values->SetString(
       "defaultSearchGroupLabel",
       l10n_util::GetStringFUTF16(IDS_SEARCH_PREF_EXPLANATION, omnibox_url));
@@ -1242,8 +1242,8 @@ scoped_ptr<DictionaryValue> BrowserOptionsHandler::GetSyncStateDictionary() {
   sync_status->SetBoolean("setupInProgress",
       service && !service->IsManaged() && service->FirstSetupInProgress());
 
-  string16 status_label;
-  string16 link_label;
+  base::string16 status_label;
+  base::string16 link_label;
   bool status_has_error = sync_ui_util::GetStatusLabels(
       service, *signin, sync_ui_util::WITH_HTML, &status_label, &link_label) ==
           sync_ui_util::SYNC_ERROR;
@@ -1457,7 +1457,7 @@ void BrowserOptionsHandler::SetupCloudPrintConnectorSection() {
   }
   base::FundamentalValue disabled(email.empty());
 
-  string16 label_str;
+  base::string16 label_str;
   if (email.empty()) {
     label_str = l10n_util::GetStringFUTF16(
         IDS_OPTIONS_CLOUD_PRINT_CONNECTOR_DISABLED_LABEL,
diff --git a/chrome/browser/ui/webui/options/certificate_manager_handler.cc b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
index df9b3f4..ce94778 100644
--- a/chrome/browser/ui/webui/options/certificate_manager_handler.cc
+++ b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
@@ -85,8 +85,8 @@ struct DictionaryIdComparator {
     DCHECK(b->GetType() == Value::TYPE_DICTIONARY);
     const DictionaryValue* a_dict = reinterpret_cast<const DictionaryValue*>(a);
     const DictionaryValue* b_dict = reinterpret_cast<const DictionaryValue*>(b);
-    string16 a_str;
-    string16 b_str;
+    base::string16 a_str;
+    base::string16 b_str;
     a_dict->GetString(kNameId, &a_str);
     b_dict->GetString(kNameId, &b_str);
     if (collator_ == NULL)
@@ -608,7 +608,7 @@ void CertificateManagerHandler::ExportPersonal(const ListValue* args) {
   select_file_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   select_file_dialog_->SelectFile(
-      ui::SelectFileDialog::SELECT_SAVEAS_FILE, string16(),
+      ui::SelectFileDialog::SELECT_SAVEAS_FILE, base::string16(),
       base::FilePath(), &file_type_info, 1, FILE_PATH_LITERAL("p12"),
       GetParentWindow(),
       reinterpret_cast<void*>(EXPORT_PERSONAL_FILE_SELECTED));
@@ -699,7 +699,7 @@ void CertificateManagerHandler::StartImportPersonal(const ListValue* args) {
   select_file_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   select_file_dialog_->SelectFile(
-      ui::SelectFileDialog::SELECT_OPEN_FILE, string16(),
+      ui::SelectFileDialog::SELECT_OPEN_FILE, base::string16(),
       base::FilePath(), &file_type_info, 1, FILE_PATH_LITERAL("p12"),
       GetParentWindow(),
       reinterpret_cast<void*>(IMPORT_PERSONAL_FILE_SELECTED));
diff --git a/chrome/browser/ui/webui/options/certificate_manager_handler.h b/chrome/browser/ui/webui/options/certificate_manager_handler.h
index 47e42011..0923309 100644
--- a/chrome/browser/ui/webui/options/certificate_manager_handler.h
+++ b/chrome/browser/ui/webui/options/certificate_manager_handler.h
@@ -173,7 +173,7 @@ class CertificateManagerHandler
   // password, etc the user chose while we wait for them to enter a password,
   // wait for file to be read, etc.
   base::FilePath file_path_;
-  string16 password_;
+  base::string16 password_;
   bool use_hardware_backed_;
   std::string file_data_;
   net::CertificateList selected_cert_list_;
diff --git a/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.cc
index 23a6a13..0f550a5 100644
--- a/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.cc
@@ -199,7 +199,7 @@ ListValue* CrosLanguageOptionsHandler::GetLanguageListInternal(
   // In theory, we should be able to create a map that is sorted by
   // display names using ICU comparator, but doing it is hard, thus we'll
   // use an auxiliary vector to achieve the same result.
-  typedef std::pair<std::string, string16> LanguagePair;
+  typedef std::pair<std::string, base::string16> LanguagePair;
   typedef std::map<string16, LanguagePair> LanguageMap;
   LanguageMap language_map;
   // The auxiliary vector mentioned above.
@@ -216,9 +216,9 @@ ListValue* CrosLanguageOptionsHandler::GetLanguageListInternal(
       continue;
     }
 
-    const string16 display_name =
+    const base::string16 display_name =
         l10n_util::GetDisplayNameForLocale(*iter, app_locale, true);
-    const string16 native_display_name =
+    const base::string16 native_display_name =
         l10n_util::GetDisplayNameForLocale(*iter, *iter, true);
 
     display_names.push_back(display_name);
@@ -238,10 +238,10 @@ ListValue* CrosLanguageOptionsHandler::GetLanguageListInternal(
     if (IsBlacklisted(base_language_codes[i]))
       continue;
 
-    string16 display_name =
+    base::string16 display_name =
         l10n_util::GetDisplayNameForLocale(
             base_language_codes[i], app_locale, false);
-    string16 native_display_name =
+    base::string16 native_display_name =
         l10n_util::GetDisplayNameForLocale(
             base_language_codes[i], base_language_codes[i], false);
     display_names.push_back(display_name);
@@ -256,7 +256,7 @@ ListValue* CrosLanguageOptionsHandler::GetLanguageListInternal(
   ListValue* language_list = new ListValue();
   for (size_t i = 0; i < display_names.size(); ++i) {
     // Sets the directionality of the display language name.
-    string16 display_name(display_names[i]);
+    base::string16 display_name(display_names[i]);
     bool markup_removal =
         base::i18n::UnadjustStringForLocaleDirection(&display_name);
     DCHECK(markup_removal);
diff --git a/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.h b/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.h
index e811f14..32bf026 100644
--- a/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.h
+++ b/chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.h
@@ -65,7 +65,7 @@ class CrosLanguageOptionsHandler
 
  private:
   // LanguageOptionsHandlerCommon implementation.
-  virtual string16 GetProductName() OVERRIDE;
+  virtual base::string16 GetProductName() OVERRIDE;
   virtual void SetApplicationLocale(const std::string& language_code) OVERRIDE;
 
   // Called when the sign-out button is clicked.
diff --git a/chrome/browser/ui/webui/options/clear_browser_data_handler.cc b/chrome/browser/ui/webui/options/clear_browser_data_handler.cc
index 0b578e0..32ff67e 100644
--- a/chrome/browser/ui/webui/options/clear_browser_data_handler.cc
+++ b/chrome/browser/ui/webui/options/clear_browser_data_handler.cc
@@ -109,7 +109,7 @@ void ClearBrowserDataHandler::GetLocalizedValues(
 
   ListValue* time_list = new ListValue;
   for (int i = 0; i < 5; i++) {
-    string16 label_string;
+    base::string16 label_string;
     switch (i) {
       case 0:
         label_string = l10n_util::GetStringUTF16(IDS_CLEAR_DATA_HOUR);
diff --git a/chrome/browser/ui/webui/options/cookies_view_handler.cc b/chrome/browser/ui/webui/options/cookies_view_handler.cc
index 006a5a5..5faf7fe 100644
--- a/chrome/browser/ui/webui/options/cookies_view_handler.cc
+++ b/chrome/browser/ui/webui/options/cookies_view_handler.cc
@@ -208,7 +208,7 @@ void CookiesViewHandler::EnsureCookiesTreeModelCreated() {
 }
 
 void CookiesViewHandler::UpdateSearchResults(const ListValue* args) {
-  string16 query;
+  base::string16 query;
   if (!args->GetString(0, &query))
     return;
 
diff --git a/chrome/browser/ui/webui/options/core_options_handler.cc b/chrome/browser/ui/webui/options/core_options_handler.cc
index ebc8bcd..cd98a73 100644
--- a/chrome/browser/ui/webui/options/core_options_handler.cc
+++ b/chrome/browser/ui/webui/options/core_options_handler.cc
@@ -415,7 +415,7 @@ void CoreOptionsHandler::HandleFetchPrefs(const ListValue* args) {
   if (!args->Get(0, &callback) || !callback->IsType(base::Value::TYPE_STRING))
     return;
 
-  string16 callback_function;
+  base::string16 callback_function;
   if (!callback->GetAsString(&callback_function))
     return;
 
diff --git a/chrome/browser/ui/webui/options/create_profile_handler.cc b/chrome/browser/ui/webui/options/create_profile_handler.cc
index f88bacc..c6b9c60 100644
--- a/chrome/browser/ui/webui/options/create_profile_handler.cc
+++ b/chrome/browser/ui/webui/options/create_profile_handler.cc
@@ -75,8 +75,8 @@ void CreateProfileHandler::CreateProfile(const ListValue* args) {
   DCHECK(profile_path_being_created_.empty());
   profile_creation_start_time_ = base::TimeTicks::Now();
 
-  string16 name;
-  string16 icon;
+  base::string16 name;
+  base::string16 icon;
   std::string managed_user_id;
   bool create_shortcut = false;
   bool managed_user = false;
@@ -222,7 +222,7 @@ void CreateProfileHandler::OnManagedUserRegistered(
     return;
   }
 
-  string16 error_msg;
+  base::string16 error_msg;
   if (state == GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS ||
       state == GoogleServiceAuthError::USER_NOT_SIGNED_UP ||
       state == GoogleServiceAuthError::ACCOUNT_DELETED ||
@@ -275,8 +275,9 @@ void CreateProfileHandler::CreateShortcutAndShowSuccess(
   profile_creation_type_ = NO_CREATION_IN_PROGRESS;
 }
 
-void CreateProfileHandler::ShowProfileCreationError(Profile* profile,
-                                                    const string16& error) {
+void CreateProfileHandler::ShowProfileCreationError(
+    Profile* profile,
+    const base::string16& error) {
   DCHECK_NE(NO_CREATION_IN_PROGRESS, profile_creation_type_);
   profile_creation_type_ = NO_CREATION_IN_PROGRESS;
   profile_path_being_created_.clear();
@@ -287,7 +288,7 @@ void CreateProfileHandler::ShowProfileCreationError(Profile* profile,
 }
 
 void CreateProfileHandler::ShowProfileCreationWarning(
-    const string16& warning) {
+    const base::string16& warning) {
   DCHECK_EQ(SUPERVISED_PROFILE_CREATION, profile_creation_type_);
   web_ui()->CallJavascriptFunction("BrowserOptions.showCreateProfileWarning",
                                    base::StringValue(warning));
@@ -361,7 +362,7 @@ void CreateProfileHandler::RecordSupervisedProfileCreationMetrics(
   }
 }
 
-string16 CreateProfileHandler::GetProfileCreationErrorMessage(
+base::string16 CreateProfileHandler::GetProfileCreationErrorMessage(
     ProfileCreationErrorType error) const {
   int message_id = -1;
   switch (error) {
diff --git a/chrome/browser/ui/webui/options/create_profile_handler.h b/chrome/browser/ui/webui/options/create_profile_handler.h
index d443df9..2c25b71 100644
--- a/chrome/browser/ui/webui/options/create_profile_handler.h
+++ b/chrome/browser/ui/webui/options/create_profile_handler.h
@@ -109,10 +109,10 @@ class CreateProfileHandler: public OptionsPageUIHandler {
                                     Profile* profile);
 
   // Updates the UI to show an error when creating a profile.
-  void ShowProfileCreationError(Profile* profile, const string16& error);
+  void ShowProfileCreationError(Profile* profile, const base::string16& error);
 
   // Updates the UI to show a non-fatal warning when creating a profile.
-  void ShowProfileCreationWarning(const string16& warning);
+  void ShowProfileCreationWarning(const base::string16& warning);
 
   // Cancels creation of a managed-user profile currently in progress, as
   // indicated by profile_path_being_created_, removing the object and files
@@ -134,7 +134,8 @@ class CreateProfileHandler: public OptionsPageUIHandler {
   void RecordSupervisedProfileCreationMetrics(
       GoogleServiceAuthError::State error_state);
 
-  string16 GetProfileCreationErrorMessage(ProfileCreationErrorType error) const;
+  base::string16 GetProfileCreationErrorMessage(
+      ProfileCreationErrorType error) const;
   std::string GetJavascriptMethodName(ProfileCreationStatus status) const;
 
   bool IsValidExistingManagedUserId(
diff --git a/chrome/browser/ui/webui/options/font_settings_handler.cc b/chrome/browser/ui/webui/options/font_settings_handler.cc
index c0de39a..4e87c11 100644
--- a/chrome/browser/ui/webui/options/font_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/font_settings_handler.cc
@@ -196,7 +196,7 @@ void FontSettingsHandler::FontsListHasLoaded(
     ListValue* font;
     bool has_font = list->GetList(i, &font);
     DCHECK(has_font);
-    string16 value;
+    base::string16 value;
     bool has_value = font->GetString(1, &value);
     DCHECK(has_value);
     bool has_rtl_chars = base::i18n::StringContainsStrongRTLChars(value);
@@ -220,7 +220,7 @@ void FontSettingsHandler::FontsListHasLoaded(
       int cmd_id = it->encoding_id;
       std::string encoding =
       CharacterEncoding::GetCanonicalEncodingNameByCommandId(cmd_id);
-      string16 name = it->encoding_display_name;
+      base::string16 name = it->encoding_display_name;
       bool has_rtl_chars = base::i18n::StringContainsStrongRTLChars(name);
       option->Append(new base::StringValue(encoding));
       option->Append(new base::StringValue(name));
diff --git a/chrome/browser/ui/webui/options/handler_options_handler.cc b/chrome/browser/ui/webui/options/handler_options_handler.cc
index b5a0398..c62edb0 100644
--- a/chrome/browser/ui/webui/options/handler_options_handler.cc
+++ b/chrome/browser/ui/webui/options/handler_options_handler.cc
@@ -185,9 +185,9 @@ void HandlerOptionsHandler::SetDefault(const ListValue* args) {
 
 ProtocolHandler HandlerOptionsHandler::ParseHandlerFromArgs(
     const ListValue* args) const {
-  string16 protocol;
-  string16 url;
-  string16 title;
+  base::string16 protocol;
+  base::string16 url;
+  base::string16 title;
   bool ok = args->GetString(0, &protocol) && args->GetString(1, &url) &&
     args->GetString(2, &title);
   if (!ok)
diff --git a/chrome/browser/ui/webui/options/home_page_overlay_handler.cc b/chrome/browser/ui/webui/options/home_page_overlay_handler.cc
index 29125dc..4496648 100644
--- a/chrome/browser/ui/webui/options/home_page_overlay_handler.cc
+++ b/chrome/browser/ui/webui/options/home_page_overlay_handler.cc
@@ -45,12 +45,12 @@ void HomePageOverlayHandler::GetLocalizedValues(
 
 void HomePageOverlayHandler::RequestAutocompleteSuggestions(
     const base::ListValue* args) {
-  string16 input;
+  base::string16 input;
   CHECK_EQ(args->GetSize(), 1U);
   CHECK(args->GetString(0, &input));
 
   autocomplete_controller_->Start(AutocompleteInput(
-      input, string16::npos, string16(), GURL(),
+      input, base::string16::npos, base::string16(), GURL(),
       AutocompleteInput::INVALID_SPEC, true,
       false, false, AutocompleteInput::ALL_MATCHES));
 }
diff --git a/chrome/browser/ui/webui/options/language_options_handler.cc b/chrome/browser/ui/webui/options/language_options_handler.cc
index c34e614..9883683 100644
--- a/chrome/browser/ui/webui/options/language_options_handler.cc
+++ b/chrome/browser/ui/webui/options/language_options_handler.cc
@@ -66,7 +66,7 @@ ListValue* LanguageOptionsHandler::GetLanguageList() {
   // In theory, we should be able to create a map that is sorted by
   // display names using ICU comparator, but doing it is hard, thus we'll
   // use an auxiliary vector to achieve the same result.
-  typedef std::pair<std::string, string16> LanguagePair;
+  typedef std::pair<std::string, base::string16> LanguagePair;
   typedef std::map<string16, LanguagePair> LanguageMap;
   LanguageMap language_map;
   // The auxiliary vector mentioned above.
@@ -74,10 +74,10 @@ ListValue* LanguageOptionsHandler::GetLanguageList() {
 
   // Build the list of display names, and build the language map.
   for (size_t i = 0; i < language_codes.size(); ++i) {
-    string16 display_name =
+    base::string16 display_name =
         l10n_util::GetDisplayNameForLocale(language_codes[i], app_locale,
                                            false);
-    string16 native_display_name =
+    base::string16 native_display_name =
         l10n_util::GetDisplayNameForLocale(language_codes[i], language_codes[i],
                                            false);
     display_names.push_back(display_name);
@@ -92,12 +92,12 @@ ListValue* LanguageOptionsHandler::GetLanguageList() {
   // Build the language list from the language map.
   ListValue* language_list = new ListValue();
   for (size_t i = 0; i < display_names.size(); ++i) {
-    string16& display_name = display_names[i];
-    string16 adjusted_display_name(display_name);
+    base::string16& display_name = display_names[i];
+    base::string16 adjusted_display_name(display_name);
     base::i18n::AdjustStringForLocaleDirection(&adjusted_display_name);
 
     const LanguagePair& pair = language_map[display_name];
-    string16 adjusted_native_display_name(pair.second);
+    base::string16 adjusted_native_display_name(pair.second);
     base::i18n::AdjustStringForLocaleDirection(&adjusted_native_display_name);
 
     bool has_rtl_chars = base::i18n::StringContainsStrongRTLChars(display_name);
diff --git a/chrome/browser/ui/webui/options/language_options_handler.h b/chrome/browser/ui/webui/options/language_options_handler.h
index 4eafe0f..b75f94f 100644
--- a/chrome/browser/ui/webui/options/language_options_handler.h
+++ b/chrome/browser/ui/webui/options/language_options_handler.h
@@ -33,7 +33,7 @@ class LanguageOptionsHandler : public LanguageOptionsHandlerCommon {
 
  private:
   // LanguageOptionsHandlerCommon implementation.
-  virtual string16 GetProductName() OVERRIDE;
+  virtual base::string16 GetProductName() OVERRIDE;
   virtual void SetApplicationLocale(const std::string& language_code) OVERRIDE;
 
   // Called when the restart button is clicked.
diff --git a/chrome/browser/ui/webui/options/language_options_handler_common.h b/chrome/browser/ui/webui/options/language_options_handler_common.h
index 6cfda8f..65b45cf 100644
--- a/chrome/browser/ui/webui/options/language_options_handler_common.h
+++ b/chrome/browser/ui/webui/options/language_options_handler_common.h
@@ -59,7 +59,7 @@ class LanguageOptionsHandlerCommon
 
  private:
   // Returns the name of the product (ex. "Chrome" or "Chrome OS").
-  virtual string16 GetProductName() = 0;
+  virtual base::string16 GetProductName() = 0;
 
   // Sets the application locale.
   virtual void SetApplicationLocale(const std::string& language_code) = 0;
diff --git a/chrome/browser/ui/webui/options/manage_profile_handler.cc b/chrome/browser/ui/webui/options/manage_profile_handler.cc
index bc1b7de..716cd08 100644
--- a/chrome/browser/ui/webui/options/manage_profile_handler.cc
+++ b/chrome/browser/ui/webui/options/manage_profile_handler.cc
@@ -313,7 +313,7 @@ void ManageProfileHandler::SetProfileIconAndName(const ListValue* args) {
   if (profile->IsManaged())
     return;
 
-  string16 new_profile_name;
+  base::string16 new_profile_name;
   if (!args->GetString(2, &new_profile_name))
     return;
 
@@ -368,7 +368,7 @@ void ManageProfileHandler::ProfileIconSelectionChanged(
   size_t profile_index = cache.GetIndexOfProfileWithPath(profile_file_path);
   if (profile_index == std::string::npos)
     return;
-  string16 gaia_name = cache.GetNameOfProfileAtIndex(profile_index);
+  base::string16 gaia_name = cache.GetNameOfProfileAtIndex(profile_index);
   if (gaia_name.empty())
     return;
 
@@ -405,7 +405,7 @@ void ManageProfileHandler::RequestCreateProfileUpdate(
   Profile* profile = Profile::FromWebUI(web_ui());
   SigninManagerBase* manager =
       SigninManagerFactory::GetForProfile(profile);
-  string16 username = UTF8ToUTF16(manager->GetAuthenticatedUsername());
+  base::string16 username = UTF8ToUTF16(manager->GetAuthenticatedUsername());
   ProfileSyncService* service =
      ProfileSyncServiceFactory::GetForProfile(profile);
   GoogleServiceAuthError::State state = service->GetAuthError().state();
diff --git a/chrome/browser/ui/webui/options/managed_user_import_handler.cc b/chrome/browser/ui/webui/options/managed_user_import_handler.cc
index ae9ef7e..86f9e7f 100644
--- a/chrome/browser/ui/webui/options/managed_user_import_handler.cc
+++ b/chrome/browser/ui/webui/options/managed_user_import_handler.cc
@@ -174,7 +174,7 @@ void ManagedUserImportHandler::SendExistingManagedUsers(
 void ManagedUserImportHandler::ClearManagedUsersAndShowError() {
   web_ui()->CallJavascriptFunction(
       "ManagedUserImportOverlay.receiveExistingManagedUsers");
-  string16 error_message =
+  base::string16 error_message =
       l10n_util::GetStringUTF16(IDS_MANAGED_USER_IMPORT_SIGN_IN_ERROR);
   web_ui()->CallJavascriptFunction("ManagedUserImportOverlay.onError",
                                    base::StringValue(error_message));
diff --git a/chrome/browser/ui/webui/options/media_galleries_handler.cc b/chrome/browser/ui/webui/options/media_galleries_handler.cc
index cef51fe5..3cf35a9 100644
--- a/chrome/browser/ui/webui/options/media_galleries_handler.cc
+++ b/chrome/browser/ui/webui/options/media_galleries_handler.cc
@@ -109,7 +109,7 @@ void MediaGalleriesHandler::HandleAddNewGallery(const base::ListValue* args) {
       new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   select_file_dialog_->SelectFile(
       ui::SelectFileDialog::SELECT_FOLDER,
-      string16(),  // TODO(estade): a name for the dialog?
+      base::string16(),  // TODO(estade): a name for the dialog?
       base::FilePath(),
       NULL, 0,
       base::FilePath::StringType(),
diff --git a/chrome/browser/ui/webui/options/options_ui.cc b/chrome/browser/ui/webui/options/options_ui.cc
index 61bd0f6..e7c2449 100644
--- a/chrome/browser/ui/webui/options/options_ui.cc
+++ b/chrome/browser/ui/webui/options/options_ui.cc
@@ -206,7 +206,7 @@ void OptionsPageUIHandler::RegisterStrings(
     const OptionsStringResource* resources,
     size_t length) {
   for (size_t i = 0; i < length; ++i) {
-    string16 value;
+    base::string16 value;
     if (resources[i].substitution_id == 0) {
       value = l10n_util::GetStringUTF16(resources[i].id);
     } else {
diff --git a/chrome/browser/ui/webui/options/options_ui_browsertest.cc b/chrome/browser/ui/webui/options/options_ui_browsertest.cc
index f185076..084b248 100644
--- a/chrome/browser/ui/webui/options/options_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/options/options_ui_browsertest.cc
@@ -66,10 +66,10 @@ void OptionsUIBrowserTest::VerifyNavbar() {
 }
 
 void OptionsUIBrowserTest::VerifyTitle() {
-  string16 title =
+  base::string16 title =
       browser()->tab_strip_model()->GetActiveWebContents()->GetTitle();
-  string16 expected_title = l10n_util::GetStringUTF16(IDS_SETTINGS_TITLE);
-  EXPECT_NE(title.find(expected_title), string16::npos);
+  base::string16 expected_title = l10n_util::GetStringUTF16(IDS_SETTINGS_TITLE);
+  EXPECT_NE(title.find(expected_title), base::string16::npos);
 }
 
 // Flaky, see http://crbug.com/119671.
@@ -117,8 +117,8 @@ IN_PROC_BROWSER_TEST_F(OptionsUIBrowserTest, NavigateBackFromOverlayDialog) {
       profile_manager->GenerateNextProfileDirectoryPath(),
       base::Bind(&RunClosureWhenProfileInitialized,
                  run_loop.QuitClosure()),
-                 string16(),
-                 string16(),
+                 base::string16(),
+                 base::string16(),
                  std::string());
   run_loop.Run();
 
diff --git a/chrome/browser/ui/webui/options/password_manager_handler.cc b/chrome/browser/ui/webui/options/password_manager_handler.cc
index 3805f1d..b605282 100644
--- a/chrome/browser/ui/webui/options/password_manager_handler.cc
+++ b/chrome/browser/ui/webui/options/password_manager_handler.cc
@@ -120,8 +120,9 @@ void PasswordManagerHandler::HandleRequestShowPassword(const ListValue* args) {
   password_manager_presenter_.RequestShowPassword(static_cast<size_t>(index));
 }
 
-void PasswordManagerHandler::ShowPassword(size_t index,
-                                          const string16& password_value) {
+void PasswordManagerHandler::ShowPassword(
+    size_t index,
+    const base::string16& password_value) {
   // Call back the front end to reveal the password.
   web_ui()->CallJavascriptFunction(
       "PasswordManager.showPassword",
@@ -138,7 +139,7 @@ void PasswordManagerHandler::SetPasswordList(
     bool show_passwords) {
   ListValue entries;
   languages_ = GetProfile()->GetPrefs()->GetString(prefs::kAcceptLanguages);
-  string16 placeholder(ASCIIToUTF16("        "));
+  base::string16 placeholder(ASCIIToUTF16("        "));
   for (size_t i = 0; i < password_list.size(); ++i) {
     ListValue* entry = new ListValue();
     entry->Append(new StringValue(net::FormatUrl(password_list[i]->origin,
@@ -149,7 +150,7 @@ void PasswordManagerHandler::SetPasswordList(
     } else {
       // Use a placeholder value with the same length as the password.
       entry->Append(new StringValue(
-          string16(password_list[i]->password_value.length(), ' ')));
+          base::string16(password_list[i]->password_value.length(), ' ')));
     }
     entries.Append(entry);
   }
diff --git a/chrome/browser/ui/webui/options/password_manager_handler.h b/chrome/browser/ui/webui/options/password_manager_handler.h
index c25b05c..11ec857 100644
--- a/chrome/browser/ui/webui/options/password_manager_handler.h
+++ b/chrome/browser/ui/webui/options/password_manager_handler.h
@@ -29,7 +29,7 @@ class PasswordManagerHandler : public OptionsPageUIHandler,
 
   // PasswordUIView implementation.
   virtual Profile* GetProfile() OVERRIDE;
-  virtual void ShowPassword(size_t index, const string16& password_value)
+  virtual void ShowPassword(size_t index, const base::string16& password_value)
       OVERRIDE;
   virtual void SetPasswordList(
       const ScopedVector<autofill::PasswordForm>& password_list,
diff --git a/chrome/browser/ui/webui/options/search_engine_manager_handler.cc b/chrome/browser/ui/webui/options/search_engine_manager_handler.cc
index e0d67c0..ed168b6 100644
--- a/chrome/browser/ui/webui/options/search_engine_manager_handler.cc
+++ b/chrome/browser/ui/webui/options/search_engine_manager_handler.cc
@@ -247,8 +247,8 @@ void SearchEngineManagerHandler::EditSearchEngine(const ListValue* args) {
 
 void SearchEngineManagerHandler::OnEditedKeyword(
     TemplateURL* template_url,
-    const string16& title,
-    const string16& keyword,
+    const base::string16& title,
+    const base::string16& keyword,
     const std::string& url) {
   DCHECK(!url.empty());
   if (template_url)
@@ -263,8 +263,8 @@ void SearchEngineManagerHandler::CheckSearchEngineInfoValidity(
 {
   if (!edit_controller_.get())
     return;
-  string16 name;
-  string16 keyword;
+  base::string16 name;
+  base::string16 keyword;
   std::string url;
   std::string modelIndex;
   if (!args->GetString(ENGINE_NAME, &name) ||
@@ -294,8 +294,8 @@ void SearchEngineManagerHandler::EditCancelled(const ListValue* args) {
 void SearchEngineManagerHandler::EditCompleted(const ListValue* args) {
   if (!edit_controller_.get())
     return;
-  string16 name;
-  string16 keyword;
+  base::string16 name;
+  base::string16 keyword;
   std::string url;
   if (!args->GetString(ENGINE_NAME, &name) ||
       !args->GetString(ENGINE_KEYWORD, &keyword) ||
diff --git a/chrome/browser/ui/webui/options/search_engine_manager_handler.h b/chrome/browser/ui/webui/options/search_engine_manager_handler.h
index 337a7da..2057d82 100644
--- a/chrome/browser/ui/webui/options/search_engine_manager_handler.h
+++ b/chrome/browser/ui/webui/options/search_engine_manager_handler.h
@@ -38,8 +38,8 @@ class SearchEngineManagerHandler : public OptionsPageUIHandler,
 
   // EditSearchEngineControllerDelegate implementation.
   virtual void OnEditedKeyword(TemplateURL* template_url,
-                               const string16& title,
-                               const string16& keyword,
+                               const base::string16& title,
+                               const base::string16& keyword,
                                const std::string& url) OVERRIDE;
 
   virtual void RegisterMessages() OVERRIDE;
diff --git a/chrome/browser/ui/webui/options/startup_pages_handler.cc b/chrome/browser/ui/webui/options/startup_pages_handler.cc
index 343b2a6..e46e9ce 100644
--- a/chrome/browser/ui/webui/options/startup_pages_handler.cc
+++ b/chrome/browser/ui/webui/options/startup_pages_handler.cc
@@ -224,12 +224,12 @@ void StartupPagesHandler::CancelChanges(const ListValue* args) {
 
 void StartupPagesHandler::RequestAutocompleteSuggestions(
     const ListValue* args) {
-  string16 input;
+  base::string16 input;
   CHECK_EQ(args->GetSize(), 1U);
   CHECK(args->GetString(0, &input));
 
   autocomplete_controller_->Start(AutocompleteInput(
-      input, string16::npos, string16(), GURL(),
+      input, base::string16::npos, base::string16(), GURL(),
       AutocompleteInput::INVALID_SPEC, true,
       false, false, AutocompleteInput::ALL_MATCHES));
 }
diff --git a/chrome/browser/ui/webui/plugins_ui.cc b/chrome/browser/ui/webui/plugins_ui.cc
index dc42f0d..0564ecd 100644
--- a/chrome/browser/ui/webui/plugins_ui.cc
+++ b/chrome/browser/ui/webui/plugins_ui.cc
@@ -106,7 +106,7 @@ content::WebUIDataSource* CreatePluginsUIHTMLSource() {
   return source;
 }
 
-string16 PluginTypeToString(int type) {
+base::string16 PluginTypeToString(int type) {
   // The type is stored as an |int|, but doing the switch on the right
   // enumeration type gives us better build-time error checking (if someone adds
   // a new type).
@@ -121,7 +121,7 @@ string16 PluginTypeToString(int type) {
       return l10n_util::GetStringUTF16(IDS_PLUGINS_PPAPI_UNSANDBOXED);
   }
   NOTREACHED();
-  return string16();
+  return base::string16();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -240,7 +240,7 @@ void PluginsDOMHandler::HandleEnablePluginMessage(const ListValue* args) {
 
   PluginPrefs* plugin_prefs = PluginPrefs::GetForProfile(profile).get();
   if (is_group_str == "true") {
-    string16 group_name;
+    base::string16 group_name;
     if (!args->GetString(0, &group_name)) {
       NOTREACHED();
       return;
@@ -249,9 +249,10 @@ void PluginsDOMHandler::HandleEnablePluginMessage(const ListValue* args) {
     plugin_prefs->EnablePluginGroup(enable, group_name);
     if (enable) {
       // See http://crbug.com/50105 for background.
-      string16 adobereader = ASCIIToUTF16(
-           PluginMetadata::kAdobeReaderGroupName);
-      string16 internalpdf = ASCIIToUTF16(ChromeContentClient::kPDFPluginName);
+      base::string16 adobereader = ASCIIToUTF16(
+          PluginMetadata::kAdobeReaderGroupName);
+      base::string16 internalpdf =
+          ASCIIToUTF16(ChromeContentClient::kPDFPluginName);
       if (group_name == adobereader)
         plugin_prefs->EnablePluginGroup(false, internalpdf);
       else if (group_name == internalpdf)
@@ -352,7 +353,7 @@ void PluginsDOMHandler::PluginsLoaded(
     ListValue* plugin_files = new ListValue();
     scoped_ptr<PluginMetadata> plugin_metadata(
         plugin_finder->GetPluginMetadata(*group_plugins[0]));
-    string16 group_name = plugin_metadata->name();
+    base::string16 group_name = plugin_metadata->name();
     std::string group_identifier = plugin_metadata->identifier();
     bool group_enabled = false;
     bool all_plugins_enabled_by_policy = true;
diff --git a/chrome/browser/ui/webui/policy_ui.cc b/chrome/browser/ui/webui/policy_ui.cc
index 3d93dc5..259e67b 100644
--- a/chrome/browser/ui/webui/policy_ui.cc
+++ b/chrome/browser/ui/webui/policy_ui.cc
@@ -139,11 +139,12 @@ void GetStatusFromCore(const policy::CloudPolicyCore* core,
 
   bool no_error = store->status() == policy::CloudPolicyStore::STATUS_OK &&
                   client && client->status() == policy::DM_STATUS_SUCCESS;
-  string16 status = store->status() == policy::CloudPolicyStore::STATUS_OK &&
-                    client && client->status() != policy::DM_STATUS_SUCCESS ?
-                        policy::FormatDeviceManagementStatus(client->status()) :
-                        policy::FormatStoreStatus(store->status(),
-                                                  store->validation_status());
+  base::string16 status =
+      store->status() == policy::CloudPolicyStore::STATUS_OK &&
+      client && client->status() != policy::DM_STATUS_SUCCESS ?
+                policy::FormatDeviceManagementStatus(client->status()) :
+                policy::FormatStoreStatus(store->status(),
+                                          store->validation_status());
   const em::PolicyData* policy = store->policy();
   std::string client_id = policy ? policy->device_id() : std::string();
   std::string username = policy ? policy->username() : std::string();
@@ -684,7 +685,7 @@ void PolicyUIHandler::GetPolicyValues(const policy::PolicyMap& map,
       value->SetString("level", "recommended");
     else
       value->SetString("level", "mandatory");
-    string16 error = errors->GetErrors(entry->first);
+    base::string16 error = errors->GetErrors(entry->first);
     if (!error.empty())
       value->SetString("error", error);
     values->Set(entry->first, value);
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
index 5af78f4..e832afe 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -758,7 +758,7 @@ void PrintPreviewHandler::HandlePrint(const ListValue* args) {
 #endif
 
   scoped_refptr<base::RefCountedBytes> data;
-  string16 title;
+  base::string16 title;
   if (!GetPreviewDataAndTitle(&data, &title)) {
     // Nothing to print, no preview available.
     return;
@@ -824,7 +824,7 @@ void PrintPreviewHandler::PrintToPdf() {
     PrintPreviewUI* print_preview_ui = static_cast<PrintPreviewUI*>(
         web_ui()->GetController());
     // Pre-populating select file dialog with print job title.
-    string16 print_job_title_utf16 = print_preview_ui->initiator_title();
+    base::string16 print_job_title_utf16 = print_preview_ui->initiator_title();
 
 #if defined(OS_WIN)
     base::FilePath::StringType print_job_title(print_job_title_utf16);
@@ -918,7 +918,7 @@ void PrintPreviewHandler::PrintWithCloudPrintDialog() {
   ReportStats();
 
   scoped_refptr<base::RefCountedBytes> data;
-  string16 title;
+  base::string16 title;
   if (!GetPreviewDataAndTitle(&data, &title)) {
     // Nothing to print, no preview available.
     return;
@@ -931,7 +931,7 @@ void PrintPreviewHandler::PrintWithCloudPrintDialog() {
       modal_parent,
       data.get(),
       title,
-      string16(),
+      base::string16(),
       std::string("application/pdf"));
 
   // Once the cloud print dialog comes up we're no longer in a background
@@ -1213,7 +1213,7 @@ void PrintPreviewHandler::SelectFile(const base::FilePath& default_filename) {
       this, new ChromeSelectFilePolicy(preview_web_contents())),
   select_file_dialog_->SelectFile(
       ui::SelectFileDialog::SELECT_SAVEAS_FILE,
-      string16(),
+      base::string16(),
       sticky_settings->save_path()->Append(default_filename),
       &file_type_info,
       0,
@@ -1258,7 +1258,7 @@ void PrintPreviewHandler::FileSelected(const base::FilePath& path,
 
 void PrintPreviewHandler::PostPrintToPdfTask() {
   scoped_refptr<base::RefCountedBytes> data;
-  string16 title;
+  base::string16 title;
   if (!GetPreviewDataAndTitle(&data, &title)) {
     NOTREACHED() << "Preview data was checked before file dialog.";
     return;
@@ -1294,7 +1294,7 @@ void PrintPreviewHandler::ClearInitiatorDetails() {
 
 bool PrintPreviewHandler::GetPreviewDataAndTitle(
     scoped_refptr<base::RefCountedBytes>* data,
-    string16* title) const {
+    base::string16* title) const {
   PrintPreviewUI* print_preview_ui = static_cast<PrintPreviewUI*>(
       web_ui()->GetController());
   scoped_refptr<base::RefCountedBytes> tmp_data;
@@ -1434,7 +1434,7 @@ void PrintPreviewHandler::StartPrivetLocalPrint(
   privet_local_print_operation_->SetTicket(print_ticket);
 
   scoped_refptr<base::RefCountedBytes> data;
-  string16 title;
+  base::string16 title;
 
   if (!GetPreviewDataAndTitle(&data, &title)) {
     base::FundamentalValue http_code_value(-1);
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.h b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
index c364b32..a35df5d 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.h
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
@@ -242,7 +242,7 @@ class PrintPreviewHandler
   void GetNumberFormatAndMeasurementSystem(base::DictionaryValue* settings);
 
   bool GetPreviewDataAndTitle(scoped_refptr<base::RefCountedBytes>* data,
-                              string16* title) const;
+                              base::string16* title) const;
 
 #if defined(USE_CUPS)
   void SaveCUPSColorSetting(const base::DictionaryValue* settings);
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_ui.cc b/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
index 0209e97..44c6171 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
@@ -209,7 +209,7 @@ content::WebUIDataSource* CreatePrintPreviewUISource() {
                              IDS_PRINT_PREVIEW_PAGE_LABEL_SINGULAR);
   source->AddLocalizedString("printPreviewPageLabelPlural",
                              IDS_PRINT_PREVIEW_PAGE_LABEL_PLURAL);
-  const string16 shortcut_text(UTF8ToUTF16(kAdvancedPrintShortcut));
+  const base::string16 shortcut_text(UTF8ToUTF16(kAdvancedPrintShortcut));
 #if defined(OS_CHROMEOS)
   source->AddString(
       "systemDialogOption",
@@ -400,7 +400,7 @@ int PrintPreviewUI::GetAvailableDraftPageCount() {
 }
 
 void PrintPreviewUI::SetInitiatorTitle(
-    const string16& job_title) {
+    const base::string16& job_title) {
   initiator_title_ = job_title;
 }
 
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_ui.h b/chrome/browser/ui/webui/print_preview/print_preview_ui.h
index 33fcd80..5d68c3b 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_ui.h
+++ b/chrome/browser/ui/webui/print_preview/print_preview_ui.h
@@ -53,9 +53,9 @@ class PrintPreviewUI : public ConstrainedWebDialogUI {
   int GetAvailableDraftPageCount();
 
   // Setters
-  void SetInitiatorTitle(const string16& initiator_title);
+  void SetInitiatorTitle(const base::string16& initiator_title);
 
-  string16 initiator_title() { return initiator_title_; }
+  base::string16 initiator_title() { return initiator_title_; }
 
   bool source_is_modifiable() { return source_is_modifiable_; }
 
@@ -191,7 +191,7 @@ class PrintPreviewUI : public ConstrainedWebDialogUI {
 
   // Store the initiator title, used for populating the print preview dialog
   // title.
-  string16 initiator_title_;
+  base::string16 initiator_title_;
 
   // Keeps track of whether OnClosePrintPreviewDialog() has been called or not.
   bool dialog_closed_;
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_ui_browsertest.cc b/chrome/browser/ui/webui/print_preview/print_preview_ui_browsertest.cc
index d4f64be..d642b0f 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_ui_browsertest.cc
@@ -96,7 +96,7 @@ IN_PROC_BROWSER_TEST_F(PrintPreviewTest, WindowedNPAPIPluginHidden) {
                                                true);
 
   // First load the page and wait for the NPAPI plugin's window to display.
-  string16 expected_title(ASCIIToUTF16("ready"));
+  base::string16 expected_title(ASCIIToUTF16("ready"));
   content::WebContents* tab =
       browser()->tab_strip_model()->GetActiveWebContents();
   content::TitleWatcher title_watcher(tab, expected_title);
diff --git a/chrome/browser/ui/webui/set_as_default_browser_ui.cc b/chrome/browser/ui/webui/set_as_default_browser_ui.cc
index 89184e2..d088966d 100644
--- a/chrome/browser/ui/webui/set_as_default_browser_ui.cc
+++ b/chrome/browser/ui/webui/set_as_default_browser_ui.cc
@@ -224,7 +224,7 @@ class SetAsDefaultBrowserDialogImpl : public ui::WebDialogDelegate,
  protected:
   // Overridden from WebDialogDelegate:
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
-  virtual string16 GetDialogTitle() const OVERRIDE;
+  virtual base::string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<WebUIMessageHandler*>* handlers) const OVERRIDE;
diff --git a/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog.h b/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog.h
index ce803be..232b48d 100644
--- a/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog.h
+++ b/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog.h
@@ -53,7 +53,7 @@ class ProfileSigninConfirmationDialog : public ui::WebDialogDelegate {
 
   // WebDialogDelegate implementation.
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
-  virtual string16 GetDialogTitle() const OVERRIDE;
+  virtual base::string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<content::WebUIMessageHandler*>* handlers) const OVERRIDE;
diff --git a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
index f74eaa0..53e48fe 100644
--- a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
+++ b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
@@ -132,8 +132,9 @@ class UserManagerScreenHandler::ProfileUpdateObserver
     user_manager_handler_->SendUserList();
   }
 
-  virtual void OnProfileWasRemoved(const base::FilePath& profile_path,
-                                   const string16& profile_name) OVERRIDE {
+  virtual void OnProfileWasRemoved(
+      const base::FilePath& profile_path,
+      const base::string16& profile_name) OVERRIDE {
     // TODO(noms): Change 'SendUserList' to 'removeUser' JS-call when
     // UserManager is able to find pod belonging to removed user.
     user_manager_handler_->SendUserList();
@@ -145,8 +146,9 @@ class UserManagerScreenHandler::ProfileUpdateObserver
     // will be called.
   }
 
-  virtual void OnProfileNameChanged(const base::FilePath& profile_path,
-                                    const string16& old_profile_name) OVERRIDE {
+  virtual void OnProfileNameChanged(
+      const base::FilePath& profile_path,
+      const base::string16& old_profile_name) OVERRIDE {
     user_manager_handler_->SendUserList();
   }
 
@@ -254,8 +256,8 @@ void UserManagerScreenHandler::HandleLaunchGuest(const base::ListValue* args) {
 }
 
 void UserManagerScreenHandler::HandleLaunchUser(const base::ListValue* args) {
-  string16 emailAddress;
-  string16 displayName;
+  base::string16 emailAddress;
+  base::string16 displayName;
 
   if (!args->GetString(0, &emailAddress) ||
       !args->GetString(1, &displayName)) {
@@ -364,10 +366,12 @@ void UserManagerScreenHandler::GetLocalizedValues(
 
   // Strings needed for the user_pod_template public account div, but not ever
   // actually displayed for desktop users.
-  localized_strings->SetString("publicAccountReminder", string16());
-  localized_strings->SetString("publicAccountEnter", string16());
-  localized_strings->SetString("publicAccountEnterAccessibleName", string16());
-  localized_strings->SetString("multiple-signin-banner-text", string16());
+  localized_strings->SetString("publicAccountReminder", base::string16());
+  localized_strings->SetString("publicAccountEnter", base::string16());
+  localized_strings->SetString("publicAccountEnterAccessibleName",
+                               base::string16());
+  localized_strings->SetString("multiple-signin-banner-text",
+                               base::string16());
  }
 
 void UserManagerScreenHandler::SendUserList() {
diff --git a/chrome/browser/ui/webui/signin/user_manager_ui_browsertest.cc b/chrome/browser/ui/webui/signin/user_manager_ui_browsertest.cc
index d1cb865..96c2366 100644
--- a/chrome/browser/ui/webui/signin/user_manager_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/signin/user_manager_ui_browsertest.cc
@@ -41,7 +41,7 @@ IN_PROC_BROWSER_TEST_F(UserManagerUIBrowserTest, PageLoads) {
   content::WebContents* web_contents =
       browser()->tab_strip_model()->GetActiveWebContents();
 
-  string16 title = web_contents->GetTitle();
+  base::string16 title = web_contents->GetTitle();
   EXPECT_EQ(l10n_util::GetStringUTF16(IDS_USER_MANAGER_SCREEN_TITLE), title);
 
   // If the page has loaded correctly, then there should be an account picker.
diff --git a/chrome/browser/ui/webui/sync_internals_ui_unittest.cc b/chrome/browser/ui/webui/sync_internals_ui_unittest.cc
index 0183aef..02ad293 100644
--- a/chrome/browser/ui/webui/sync_internals_ui_unittest.cc
+++ b/chrome/browser/ui/webui/sync_internals_ui_unittest.cc
@@ -48,7 +48,7 @@ class TestSyncWebUI: public WebUI {
       : WebUI(web_contents) {}
   virtual ~TestSyncWebUI() {}
 
-  MOCK_METHOD1(ExecuteJavascript, void(const string16&));
+  MOCK_METHOD1(ExecuteJavascript, void(const base::string16&));
 };
 
 // Tests with non-NULL ProfileSyncService.
diff --git a/chrome/browser/ui/webui/sync_setup_handler.cc b/chrome/browser/ui/webui/sync_setup_handler.cc
index 80e4c9c..8d595ec 100644
--- a/chrome/browser/ui/webui/sync_setup_handler.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler.cc
@@ -199,7 +199,7 @@ void SyncSetupHandler::GetStaticLocalizedValues(
     content::WebUI* web_ui) {
   DCHECK(localized_strings);
 
-  string16 product_name(GetStringUTF16(IDS_PRODUCT_NAME));
+  base::string16 product_name(GetStringUTF16(IDS_PRODUCT_NAME));
   localized_strings->SetString(
       "chooseDataTypesInstructions",
       GetStringFUTF16(IDS_SYNC_CHOOSE_DATATYPES_INSTRUCTIONS, product_name));
@@ -367,7 +367,8 @@ void SyncSetupHandler::DisplayConfigureSync(bool show_advanced,
   base::Time passphrase_time = service->GetExplicitPassphraseTime();
   syncer::PassphraseType passphrase_type = service->GetPassphraseType();
   if (!passphrase_time.is_null()) {
-    string16 passphrase_time_str = base::TimeFormatShortDate(passphrase_time);
+    base::string16 passphrase_time_str =
+        base::TimeFormatShortDate(passphrase_time);
     args.SetString(
         "enterPassphraseBody",
         GetStringFUTF16(IDS_SYNC_ENTER_PASSPHRASE_BODY_WITH_DATE,
diff --git a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
index e40ccc3..b72c06b 100644
--- a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
@@ -196,10 +196,10 @@ class TestWebUI : public content::WebUI {
   virtual ui::ScaleFactor GetDeviceScaleFactor() const OVERRIDE {
     return ui::SCALE_FACTOR_100P;
   }
-  virtual const string16& GetOverriddenTitle() const OVERRIDE {
+  virtual const base::string16& GetOverriddenTitle() const OVERRIDE {
     return temp_string_;
   }
-  virtual void OverrideTitle(const string16& title) OVERRIDE {}
+  virtual void OverrideTitle(const base::string16& title) OVERRIDE {}
   virtual content::PageTransition GetLinkTransitionType() const OVERRIDE {
     return content::PAGE_TRANSITION_LINK;
   }
@@ -240,7 +240,7 @@ class TestWebUI : public content::WebUI {
   const std::vector<CallData>& call_data() { return call_data_; }
  private:
   std::vector<CallData> call_data_;
-  string16 temp_string_;
+  base::string16 temp_string_;
 };
 
 class TestingSyncSetupHandler : public SyncSetupHandler {
diff --git a/chrome/browser/ui/webui/task_manager/task_manager_dialog.cc b/chrome/browser/ui/webui/task_manager/task_manager_dialog.cc
index 221df31..b4228cf 100644
--- a/chrome/browser/ui/webui/task_manager/task_manager_dialog.cc
+++ b/chrome/browser/ui/webui/task_manager/task_manager_dialog.cc
@@ -63,7 +63,7 @@ class TaskManagerDialogImpl : public WebDialogDelegate {
   virtual ui::ModalType GetDialogModalType() const OVERRIDE {
     return ui::MODAL_TYPE_NONE;
   }
-  virtual string16 GetDialogTitle() const OVERRIDE {
+  virtual base::string16 GetDialogTitle() const OVERRIDE {
     return l10n_util::GetStringUTF16(IDS_TASK_MANAGER_TITLE);
   }
   virtual std::string GetDialogName() const OVERRIDE {
diff --git a/chrome/browser/ui/webui/task_manager/task_manager_handler.cc b/chrome/browser/ui/webui/task_manager/task_manager_handler.cc
index f9dc4f9..81aa206 100644
--- a/chrome/browser/ui/webui/task_manager/task_manager_handler.cc
+++ b/chrome/browser/ui/webui/task_manager/task_manager_handler.cc
@@ -110,7 +110,7 @@ void TaskManagerHandler::RegisterMessages() {
 
 static int parseIndex(const Value* value) {
   int index = -1;
-  string16 string16_index;
+  base::string16 base::string16_index;
   double double_index;
   if (value->GetAsString(&string16_index)) {
     bool converted = base::StringToInt(string16_index, &index);
diff --git a/chrome/browser/ui/webui/translate_internals/translate_internals_ui.cc b/chrome/browser/ui/webui/translate_internals/translate_internals_ui.cc
index d09e512..d3c2429 100644
--- a/chrome/browser/ui/webui/translate_internals/translate_internals_ui.cc
+++ b/chrome/browser/ui/webui/translate_internals/translate_internals_ui.cc
@@ -37,7 +37,7 @@ void GetLanguages(base::DictionaryValue* dict) {
   for (std::vector<std::string>::iterator it = language_codes.begin();
        it != language_codes.end(); ++it) {
     const std::string& lang_code = *it;
-    string16 lang_name =
+    base::string16 lang_name =
         l10n_util::GetDisplayNameForLocale(lang_code, app_locale, false);
     dict->SetString(lang_code, lang_name);
   }
diff --git a/chrome/browser/ui/webui/version_handler.cc b/chrome/browser/ui/webui/version_handler.cc
index b46de41..6074c10 100644
--- a/chrome/browser/ui/webui/version_handler.cc
+++ b/chrome/browser/ui/webui/version_handler.cc
@@ -23,8 +23,8 @@ namespace {
 
 // Retrieves the executable and profile paths on the FILE thread.
 void GetFilePaths(const base::FilePath& profile_path,
-                  string16* exec_path_out,
-                  string16* profile_path_out) {
+                  base::string16* exec_path_out,
+                  base::string16* profile_path_out) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
 
   base::FilePath executable_path = base::MakeAbsoluteFilePath(
@@ -72,8 +72,8 @@ void VersionHandler::HandleRequestVersionInfo(const ListValue* args) {
 
   // Grab the executable path on the FILE thread. It is returned in
   // OnGotFilePaths.
-  string16* exec_path_buffer = new string16;
-  string16* profile_path_buffer = new string16;
+  base::string16* exec_path_buffer = new base::string16;
+  base::string16* profile_path_buffer = new base::string16;
   content::BrowserThread::PostTaskAndReply(
       content::BrowserThread::FILE, FROM_HERE,
           base::Bind(&GetFilePaths, Profile::FromWebUI(web_ui())->GetPath(),
@@ -115,7 +115,7 @@ void VersionHandler::HandleRequestVersionInfo(const ListValue* args) {
 }
 
 void VersionHandler::OnGotFilePaths(string16* executable_path_data,
-                                    string16* profile_path_data) {
+                                    base::string16* profile_path_data) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   StringValue exec_path(*executable_path_data);
@@ -130,7 +130,7 @@ void VersionHandler::OnGotPlugins(
   std::vector<content::WebPluginInfo> info_array;
   content::PluginService::GetInstance()->GetPluginInfoArray(
       GURL(), content::kFlashPluginSwfMimeType, false, &info_array, NULL);
-  string16 flash_version =
+  base::string16 flash_version =
       l10n_util::GetStringUTF16(IDS_PLUGINS_DISABLED_PLUGIN);
   PluginPrefs* plugin_prefs =
       PluginPrefs::GetForProfile(Profile::FromWebUI(web_ui())).get();
diff --git a/chrome/browser/ui/webui/version_handler.h b/chrome/browser/ui/webui/version_handler.h
index 2fc65d4..a5affc2 100644
--- a/chrome/browser/ui/webui/version_handler.h
+++ b/chrome/browser/ui/webui/version_handler.h
@@ -30,7 +30,7 @@ class VersionHandler : public content::WebUIMessageHandler {
   // Callback which handles returning the executable and profile paths to the
   // front end.
   void OnGotFilePaths(string16* executable_path_data,
-                      string16* profile_path_data);
+                      base::string16* profile_path_data);
 
   // Callback for GetPlugins which responds to the page with the Flash version.
   // This also initiates the OS Version load on ChromeOS.
diff --git a/chrome/browser/ui/webui/web_ui_test_handler.cc b/chrome/browser/ui/webui/web_ui_test_handler.cc
index 2cbcf1a..0c347e4 100644
--- a/chrome/browser/ui/webui/web_ui_test_handler.cc
+++ b/chrome/browser/ui/webui/web_ui_test_handler.cc
@@ -27,25 +27,26 @@ WebUITestHandler::WebUITestHandler()
       is_waiting_(false) {
 }
 
-void WebUITestHandler::PreloadJavaScript(const string16& js_text,
+void WebUITestHandler::PreloadJavaScript(const base::string16& js_text,
                                          RenderViewHost* preload_host) {
   DCHECK(preload_host);
   preload_host->Send(new ChromeViewMsg_WebUIJavaScript(
-      preload_host->GetRoutingID(), string16(), js_text, 0,
+      preload_host->GetRoutingID(), base::string16(), js_text, 0,
       false));
 }
 
-void WebUITestHandler::RunJavaScript(const string16& js_text) {
+void WebUITestHandler::RunJavaScript(const base::string16& js_text) {
   web_ui()->GetWebContents()->GetRenderViewHost()->ExecuteJavascriptInWebFrame(
-      string16(), js_text);
+      base::string16(), js_text);
 }
 
-bool WebUITestHandler::RunJavaScriptTestWithResult(const string16& js_text) {
+bool WebUITestHandler::RunJavaScriptTestWithResult(
+    const base::string16& js_text) {
   test_succeeded_ = false;
   run_test_succeeded_ = false;
   RenderViewHost* rvh = web_ui()->GetWebContents()->GetRenderViewHost();
   rvh->ExecuteJavascriptInWebFrameCallbackResult(
-      string16(),  // frame_xpath
+      base::string16(),  // frame_xpath
       js_text,
       base::Bind(&WebUITestHandler::JavaScriptComplete,
                  base::Unretained(this)));
diff --git a/chrome/browser/ui/webui/web_ui_test_handler.h b/chrome/browser/ui/webui/web_ui_test_handler.h
index 91b6321..04cd7c6 100644
--- a/chrome/browser/ui/webui/web_ui_test_handler.h
+++ b/chrome/browser/ui/webui/web_ui_test_handler.h
@@ -25,15 +25,15 @@ class WebUITestHandler : public content::WebUIMessageHandler {
 
   // Sends a message through |preload_host| with the |js_text| to preload at the
   // appropriate time before the onload call is made.
-  void PreloadJavaScript(const string16& js_text,
+  void PreloadJavaScript(const base::string16& js_text,
                          content::RenderViewHost* preload_host);
 
   // Runs |js_text| in this object's WebUI frame. Does not wait for any result.
-  void RunJavaScript(const string16& js_text);
+  void RunJavaScript(const base::string16& js_text);
 
   // Runs |js_text| in this object's WebUI frame. Waits for result, logging an
   // error message on failure. Returns test pass/fail.
-  bool RunJavaScriptTestWithResult(const string16& js_text);
+  bool RunJavaScriptTestWithResult(const base::string16& js_text);
 
   // WebUIMessageHandler overrides.
   // Add test handlers to the current WebUI object.
diff --git a/chrome/browser/ui/webui/welcome_ui_android.cc b/chrome/browser/ui/webui/welcome_ui_android.cc
index 7a1579d..b5321a8 100644
--- a/chrome/browser/ui/webui/welcome_ui_android.cc
+++ b/chrome/browser/ui/webui/welcome_ui_android.cc
@@ -54,7 +54,7 @@ WelcomeUI::WelcomeUI(content::WebUI* web_ui)
   bool tos_visible = tab && tab->ShouldWelcomePageLinkToTermsOfService();
   html_source->AddBoolean("tosVisible", tos_visible);
 
-  string16 tos_html;
+  base::string16 tos_html;
   if (tos_visible) {
     std::string privacy_notice_url =
         base::StringPrintf(kPrivacyNoticeBaseURL, locale.c_str());