Switch Extensions::TabHelper to use WebContents, WebContentsUserData.

BUG=107201
TEST=no visible change
TBR=ben@chromium.org


Review URL: https://chromiumcodereview.appspot.com/10917026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155743 0039d316-1c4b-4281-b951-d872f2087c98

43 files changed, 245 insertions, 199 deletions

diff --git a/chrome/browser/extensions/active_tab_unittest.cc b/chrome/browser/extensions/active_tab_unittest.cc
index d757124..c38a8e2 100644
--- a/chrome/browser/extensions/active_tab_unittest.cc
+++ b/chrome/browser/extensions/active_tab_unittest.cc
@@ -67,8 +67,8 @@ class ActiveTabTest : public TabContentsTestHarness {
   }
 
   ActiveTabPermissionManager* active_tab_permission_manager() {
-    return tab_contents()->extension_tab_helper()->
-                           active_tab_permission_manager();
+    return extensions::TabHelper::FromWebContents(web_contents())->
+        active_tab_permission_manager();
   }
 
   bool IsAllowed(const scoped_refptr<const Extension>& extension,
diff --git a/chrome/browser/extensions/api/extension_action/extension_actions_api.cc b/chrome/browser/extensions/api/extension_action/extension_actions_api.cc
index 7b4cd1f..3fb1c97 100644
--- a/chrome/browser/extensions/api/extension_action/extension_actions_api.cc
+++ b/chrome/browser/extensions/api/extension_action/extension_actions_api.cc
@@ -341,7 +341,8 @@ void ExtensionActionFunction::NotifyBrowserActionChange() {
 }
 
 void ExtensionActionFunction::NotifyLocationBarChange() {
-  contents_->extension_tab_helper()->location_bar_controller()->NotifyChange();
+  extensions::TabHelper::FromWebContents(contents_->web_contents())->
+      location_bar_controller()->NotifyChange();
 }
 
 // static
@@ -390,7 +391,7 @@ bool ExtensionActionFunction::SetVisible(bool visible) {
 
 extensions::TabHelper& ExtensionActionFunction::tab_helper() const {
   CHECK(contents_);
-  return *contents_->extension_tab_helper();
+  return *extensions::TabHelper::FromWebContents(contents_->web_contents());
 }
 
 bool ExtensionActionShowFunction::RunExtensionAction() {
diff --git a/chrome/browser/extensions/api/extension_action/extension_page_actions_api.cc b/chrome/browser/extensions/api/extension_action/extension_page_actions_api.cc
index eff7b16..55cba75 100644
--- a/chrome/browser/extensions/api/extension_action/extension_page_actions_api.cc
+++ b/chrome/browser/extensions/api/extension_action/extension_page_actions_api.cc
@@ -99,7 +99,8 @@ bool PageActionsFunction::SetPageActionEnabled(bool enable) {
       tab_id, enable ? ExtensionAction::ACTIVE : ExtensionAction::INVISIBLE);
   page_action->SetTitle(tab_id, title);
   page_action->SetIconIndex(tab_id, icon_id);
-  contents->extension_tab_helper()->location_bar_controller()->NotifyChange();
+  extensions::TabHelper::FromWebContents(contents->web_contents())->
+      location_bar_controller()->NotifyChange();
 
   return true;
 }
diff --git a/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc b/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
index 8e9a3c1..ca0f1f1 100644
--- a/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
+++ b/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
@@ -38,8 +38,9 @@ IN_PROC_BROWSER_TEST_F(ScriptBadgeApiTest, Basics) {
   ExtensionAction* script_badge = extension->script_badge();
   ASSERT_TRUE(script_badge);
   const extensions::LocationBarController* location_bar_controller =
-      chrome::GetActiveTabContents(browser())->extension_tab_helper()->
-      location_bar_controller();
+      extensions::TabHelper::FromWebContents(
+          chrome::GetActiveWebContents(browser()))->
+              location_bar_controller();
 
   const int tab_id = SessionID::IdForTab(
       chrome::GetActiveTabContents(browser()));
diff --git a/chrome/browser/extensions/api/omnibox/omnibox_api.cc b/chrome/browser/extensions/api/omnibox/omnibox_api.cc
index 85b352b..efe9f07 100644
--- a/chrome/browser/extensions/api/omnibox/omnibox_api.cc
+++ b/chrome/browser/extensions/api/omnibox/omnibox_api.cc
@@ -84,8 +84,8 @@ void ExtensionOmniboxEventRouter::OnInputEntered(
       ExtensionSystem::Get(profile)->extension_service()->extensions()->
           GetByID(extension_id);
   CHECK(extension);
-  tab_contents->extension_tab_helper()->active_tab_permission_manager()->
-      GrantIfRequested(extension);
+  extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+      active_tab_permission_manager()->GrantIfRequested(extension);
 
   scoped_ptr<ListValue> args(new ListValue());
   args->Set(0, Value::CreateStringValue(input));
diff --git a/chrome/browser/extensions/api/tabs/execute_code_in_tab_function.cc b/chrome/browser/extensions/api/tabs/execute_code_in_tab_function.cc
index 43da953..5b76613 100644
--- a/chrome/browser/extensions/api/tabs/execute_code_in_tab_function.cc
+++ b/chrome/browser/extensions/api/tabs/execute_code_in_tab_function.cc
@@ -265,13 +265,14 @@ bool ExecuteCodeInTabFunction::Execute(const std::string& code_string) {
   }
   CHECK_NE(UserScript::UNDEFINED, run_at);
 
-  contents->extension_tab_helper()->script_executor()->ExecuteScript(
-      extension->id(),
-      script_type,
-      code_string,
-      frame_scope,
-      run_at,
-      ScriptExecutor::ISOLATED_WORLD,
-      base::Bind(&ExecuteCodeInTabFunction::OnExecuteCodeFinished, this));
+  extensions::TabHelper::FromWebContents(contents->web_contents())->
+      script_executor()->ExecuteScript(
+          extension->id(),
+          script_type,
+          code_string,
+          frame_scope,
+          run_at,
+          ScriptExecutor::ISOLATED_WORLD,
+          base::Bind(&ExecuteCodeInTabFunction::OnExecuteCodeFinished, this));
   return true;
 }
diff --git a/chrome/browser/extensions/api/tabs/tabs.cc b/chrome/browser/extensions/api/tabs/tabs.cc
index 1156651..d93d3d9 100644
--- a/chrome/browser/extensions/api/tabs/tabs.cc
+++ b/chrome/browser/extensions/api/tabs/tabs.cc
@@ -618,8 +618,10 @@ bool CreateWindowFunction::RunImpl() {
   for (std::vector<GURL>::iterator i = urls.begin(); i != urls.end(); ++i) {
     TabContents* tab = chrome::AddSelectedTabWithURL(
         new_window, *i, content::PAGE_TRANSITION_LINK);
-    if (window_type == Browser::TYPE_PANEL)
-      tab->extension_tab_helper()->SetExtensionAppIconById(extension_id);
+    if (window_type == Browser::TYPE_PANEL) {
+      extensions::TabHelper::FromWebContents(tab->web_contents())->
+          SetExtensionAppIconById(extension_id);
+    }
   }
   if (contents) {
     TabStripModel* target_tab_strip = new_window->tab_strip_model();
@@ -1349,14 +1351,15 @@ bool UpdateTabFunction::UpdateURLIfPresent(DictionaryValue* update_props,
       return false;
     }
 
-    tab_contents_->extension_tab_helper()->script_executor()->ExecuteScript(
-        extension_id(),
-        ScriptExecutor::JAVASCRIPT,
-        url.path(),
-        ScriptExecutor::TOP_FRAME,
-        extensions::UserScript::DOCUMENT_IDLE,
-        ScriptExecutor::MAIN_WORLD,
-        base::Bind(&UpdateTabFunction::OnExecuteCodeFinished, this));
+    extensions::TabHelper::FromWebContents(tab_contents_->web_contents())->
+        script_executor()->ExecuteScript(
+            extension_id(),
+            ScriptExecutor::JAVASCRIPT,
+            url.path(),
+            ScriptExecutor::TOP_FRAME,
+            extensions::UserScript::DOCUMENT_IDLE,
+            ScriptExecutor::MAIN_WORLD,
+            base::Bind(&UpdateTabFunction::OnExecuteCodeFinished, this));
 
     *is_async = true;
     return true;
diff --git a/chrome/browser/extensions/extension_toolbar_model.cc b/chrome/browser/extensions/extension_toolbar_model.cc
index 13c5e3f..a7b5b27 100644
--- a/chrome/browser/extensions/extension_toolbar_model.cc
+++ b/chrome/browser/extensions/extension_toolbar_model.cc
@@ -121,8 +121,8 @@ ExtensionToolbarModel::Action ExtensionToolbarModel::ExecuteBrowserAction(
   if (!browser_action->GetIsVisible(tab_id))
     return ACTION_NONE;
 
-  tab_contents->extension_tab_helper()->active_tab_permission_manager()->
-      GrantIfRequested(extension);
+  extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+      active_tab_permission_manager()->GrantIfRequested(extension);
 
   if (browser_action->HasPopup(tab_id)) {
     if (popup_url_out)
diff --git a/chrome/browser/extensions/menu_manager.cc b/chrome/browser/extensions/menu_manager.cc
index e8d3689..bd2e0eb 100644
--- a/chrome/browser/extensions/menu_manager.cc
+++ b/chrome/browser/extensions/menu_manager.cc
@@ -642,7 +642,7 @@ void MenuManager::ExecuteCommand(Profile* profile,
   // Add the tab info to the argument list.
   // No tab info in a platform app.
   if (!extension || !extension->is_platform_app()) {
-    // Note: web_contents only NULL in unit tests :(
+    // Note: web_contents are NULL in unit tests :(
     if (web_contents)
       args->Append(ExtensionTabUtil::CreateTabValue(web_contents, extension));
     else
@@ -666,11 +666,10 @@ void MenuManager::ExecuteCommand(Profile* profile,
       WriteToStorage(extension);
   }
 
-  TabContents* tab_contents = web_contents ?
-      TabContents::FromWebContents(web_contents) : NULL;
-  if (tab_contents && extension) {
-    tab_contents->extension_tab_helper()->active_tab_permission_manager()->
-        GrantIfRequested(extension);
+  // Note: web_contents are NULL in unit tests :(
+  if (web_contents && extensions::TabHelper::FromWebContents(web_contents)) {
+    extensions::TabHelper::FromWebContents(web_contents)->
+        active_tab_permission_manager()->GrantIfRequested(extension);
   }
 
   event_router->DispatchEventToExtension(
diff --git a/chrome/browser/extensions/page_action_controller.cc b/chrome/browser/extensions/page_action_controller.cc
index 0a706c2..e6ba8dc 100644
--- a/chrome/browser/extensions/page_action_controller.cc
+++ b/chrome/browser/extensions/page_action_controller.cc
@@ -53,9 +53,8 @@ LocationBarController::Action PageActionController::OnClicked(
   CHECK(page_action);
   int tab_id = ExtensionTabUtil::GetTabId(web_contents());
 
-  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
-  tab_contents->extension_tab_helper()->active_tab_permission_manager()->
-      GrantIfRequested(extension);
+  extensions::TabHelper::FromWebContents(web_contents())->
+      active_tab_permission_manager()->GrantIfRequested(extension);
 
   switch (mouse_button) {
     case 1:  // left
@@ -64,7 +63,7 @@ LocationBarController::Action PageActionController::OnClicked(
         return ACTION_SHOW_POPUP;
 
       GetExtensionService()->browser_event_router()->PageActionExecuted(
-          tab_contents->profile(),
+          Profile::FromBrowserContext(web_contents()->GetBrowserContext()),
           *page_action,
           tab_id,
           web_contents()->GetURL().spec(),
diff --git a/chrome/browser/extensions/script_badge_controller.cc b/chrome/browser/extensions/script_badge_controller.cc
index 5b8cbba..db573ab 100644
--- a/chrome/browser/extensions/script_badge_controller.cc
+++ b/chrome/browser/extensions/script_badge_controller.cc
@@ -76,10 +76,10 @@ LocationBarController::Action ScriptBadgeController::OnClicked(
   switch (mouse_button) {
     case 1:    // left
     case 2: {  // middle
-      TabContents* tab_contents = TabContents::FromWebContents(web_contents());
-      tab_contents->extension_tab_helper()->active_tab_permission_manager()->
-          GrantIfRequested(extension);
+      extensions::TabHelper::FromWebContents(web_contents())->
+          active_tab_permission_manager()->GrantIfRequested(extension);
 
+      TabContents* tab_contents = TabContents::FromWebContents(web_contents());
       // Even if clicking the badge doesn't immediately cause the extension to
       // run script on the page, we want to help users associate clicking with
       // the extension having permission to modify the page, so we make the icon
diff --git a/chrome/browser/extensions/script_badge_controller_unittest.cc b/chrome/browser/extensions/script_badge_controller_unittest.cc
index 0ebd81c..760d104 100644
--- a/chrome/browser/extensions/script_badge_controller_unittest.cc
+++ b/chrome/browser/extensions/script_badge_controller_unittest.cc
@@ -43,7 +43,7 @@ class ScriptBadgeControllerTest : public TabContentsTestHarness {
 
   virtual void SetUp() OVERRIDE {
     // Note that this sets a PageActionController into the
-    // extension_tab_helper()->location_bar_controller() field.  Do
+    // extensions::TabHelper's location_bar_controller field.  Do
     // not use that for testing.
     TabContentsTestHarness::SetUp();
 
diff --git a/chrome/browser/extensions/tab_helper.cc b/chrome/browser/extensions/tab_helper.cc
index 52b7656a..bfe97b8 100644
--- a/chrome/browser/extensions/tab_helper.cc
+++ b/chrome/browser/extensions/tab_helper.cc
@@ -4,8 +4,8 @@
 
 #include "chrome/browser/extensions/tab_helper.h"
 
-#include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/app_notify_channel_ui.h"
+#include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/extensions/page_action_controller.h"
@@ -15,7 +15,6 @@
 #include "chrome/browser/sessions/session_id.h"
 #include "chrome/browser/ui/browser_dialogs.h"
 #include "chrome/browser/ui/tab_contents/tab_contents.h"
-#include "chrome/browser/ui/tab_contents/tab_contents_iterator.h"
 #include "chrome/browser/ui/web_applications/web_app_ui.h"
 #include "chrome/browser/web_applications/web_app.h"
 #include "chrome/common/chrome_notification_types.h"
@@ -52,43 +51,41 @@ const char kPermissionError[] = "permission_error";
 
 namespace extensions {
 
-TabHelper::TabHelper(TabContents* tab_contents)
-    : content::WebContentsObserver(tab_contents->web_contents()),
+int TabHelper::kUserDataKey;
+
+TabHelper::TabHelper(content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents),
       extension_app_(NULL),
       ALLOW_THIS_IN_INITIALIZER_LIST(
-          extension_function_dispatcher_(tab_contents->profile(), this)),
+          extension_function_dispatcher_(
+              Profile::FromBrowserContext(web_contents->GetBrowserContext()),
+              this)),
       pending_web_app_action_(NONE),
-      tab_contents_(tab_contents),
-      script_executor_(tab_contents->web_contents()),
+      script_executor_(web_contents),
       active_tab_permission_manager_(
-          tab_contents->web_contents(),
-          SessionID::IdForTab(tab_contents),
-          tab_contents->profile()) {
+          web_contents,
+          SessionID::IdForTab(TabContents::FromWebContents(web_contents)),
+          Profile::FromBrowserContext(web_contents->GetBrowserContext())) {
   if (switch_utils::AreScriptBadgesEnabled()) {
-    location_bar_controller_.reset(new ScriptBadgeController(
-        tab_contents->web_contents(), &script_executor_));
+    location_bar_controller_.reset(
+        new ScriptBadgeController(web_contents, &script_executor_));
   } else {
     location_bar_controller_.reset(
-        new PageActionController(tab_contents->web_contents()));
+        new PageActionController(web_contents));
   }
   registrar_.Add(this,
                  content::NOTIFICATION_LOAD_STOP,
                  content::Source<NavigationController>(
-                    &tab_contents->web_contents()->GetController()));
+                    &web_contents->GetController()));
 }
 
 TabHelper::~TabHelper() {
 }
 
-void TabHelper::CopyStateFrom(const TabHelper& source) {
-  SetExtensionApp(source.extension_app());
-  extension_app_icon_ = source.extension_app_icon_;
-}
-
 void TabHelper::CreateApplicationShortcuts() {
   DCHECK(CanCreateApplicationShortcuts());
   NavigationEntry* entry =
-      tab_contents_->web_contents()->GetController().GetLastCommittedEntry();
+      web_contents()->GetController().GetLastCommittedEntry();
   if (!entry)
     return;
 
@@ -103,7 +100,7 @@ bool TabHelper::CanCreateApplicationShortcuts() const {
 #if defined(OS_MACOSX)
   return false;
 #else
-  return web_app::IsValidUrl(tab_contents_->web_contents()->GetURL()) &&
+  return web_app::IsValidUrl(web_contents()->GetURL()) &&
       pending_web_app_action_ == NONE;
 #endif
 }
@@ -140,9 +137,10 @@ SkBitmap* TabHelper::GetExtensionAppIcon() {
 }
 
 void TabHelper::RenderViewCreated(RenderViewHost* render_view_host) {
+  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
   render_view_host->Send(
       new ExtensionMsg_SetTabId(render_view_host->GetRoutingID(),
-                                SessionID::IdForTab(tab_contents_)));
+                                SessionID::IdForTab(tab_contents)));
 }
 
 void TabHelper::DidNavigateMainFrame(
@@ -157,11 +155,12 @@ void TabHelper::DidNavigateMainFrame(
   if (!service)
     return;
 
+  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
   for (ExtensionSet::const_iterator it = service->extensions()->begin();
        it != service->extensions()->end(); ++it) {
     ExtensionAction* browser_action = (*it)->browser_action();
     if (browser_action) {
-      browser_action->ClearAllValuesForTab(SessionID::IdForTab(tab_contents_));
+      browser_action->ClearAllValuesForTab(SessionID::IdForTab(tab_contents));
       content::NotificationService::current()->Notify(
           chrome::NOTIFICATION_EXTENSION_BROWSER_ACTION_UPDATED,
           content::Source<ExtensionAction>(browser_action),
@@ -189,6 +188,18 @@ bool TabHelper::OnMessageReceived(const IPC::Message& message) {
   return handled;
 }
 
+void TabHelper::DidCloneToNewWebContents(WebContents* old_web_contents,
+                                         WebContents* new_web_contents) {
+  // When the WebContents that this is attached to is cloned, give the new clone
+  // a TabHelper and copy state over.
+  CreateForWebContents(new_web_contents);
+  TabHelper* new_helper = FromWebContents(new_web_contents);
+
+  new_helper->SetExtensionApp(extension_app());
+  new_helper->extension_app_icon_ = extension_app_icon_;
+}
+
+
 void TabHelper::OnDidGetApplicationInfo(int32 page_id,
                                         const WebApplicationInfo& info) {
   // Android does not implement BrowserWindow.
@@ -196,19 +207,20 @@ void TabHelper::OnDidGetApplicationInfo(int32 page_id,
   web_app_info_ = info;
 
   NavigationEntry* entry =
-      tab_contents_->web_contents()->GetController().GetLastCommittedEntry();
+      web_contents()->GetController().GetLastCommittedEntry();
   if (!entry || (entry->GetPageID() != page_id))
     return;
 
+  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
   switch (pending_web_app_action_) {
     case CREATE_SHORTCUT: {
       chrome::ShowCreateWebAppShortcutsDialog(
-          tab_contents_->web_contents()->GetView()->GetTopLevelNativeWindow(),
-          tab_contents_);
+          web_contents()->GetView()->GetTopLevelNativeWindow(),
+          tab_contents);
       break;
     }
     case UPDATE_SHORTCUT: {
-      web_app::UpdateShortcutForTabContents(tab_contents_);
+      web_app::UpdateShortcutForTabContents(tab_contents);
       break;
     }
     default:
@@ -230,10 +242,10 @@ void TabHelper::OnInstallApplication(const WebApplicationInfo& info) {
   ExtensionInstallPrompt* prompt = NULL;
   if (extension_service->show_extensions_prompts()) {
     gfx::NativeWindow parent =
-        tab_contents_->web_contents()->GetView()->GetTopLevelNativeWindow();
-    prompt = new ExtensionInstallPrompt(parent,
-                                        tab_contents_->web_contents(),
-                                        tab_contents_->profile());
+        web_contents()->GetView()->GetTopLevelNativeWindow();
+    Profile* profile =
+        Profile::FromBrowserContext(web_contents()->GetBrowserContext());
+    prompt = new ExtensionInstallPrompt(parent, web_contents(), profile);
   }
   scoped_refptr<CrxInstaller> installer(
       CrxInstaller::Create(extension_service, prompt));
@@ -264,8 +276,7 @@ void TabHelper::OnGetAppNotifyChannel(const GURL& requestor_url,
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
   ExtensionService* extension_service = profile->GetExtensionService();
   ProcessMap* process_map = extension_service->process_map();
-  content::RenderProcessHost* process =
-      tab_contents()->web_contents()->GetRenderProcessHost();
+  content::RenderProcessHost* process = web_contents()->GetRenderProcessHost();
   const Extension* extension =
       extension_service->GetInstalledApp(requestor_url);
 
@@ -287,8 +298,9 @@ void TabHelper::OnGetAppNotifyChannel(const GURL& requestor_url,
     return;
   }
 
+  TabContents* tab_contents = TabContents::FromWebContents(web_contents());
   AppNotifyChannelUI* ui = AppNotifyChannelUI::Create(
-      profile, tab_contents(), extension->name(),
+      profile, tab_contents, extension->name(),
       AppNotifyChannelUI::NOTIFICATION_INFOBAR);
 
   scoped_refptr<AppNotifyChannelSetup> channel_setup(
@@ -427,7 +439,7 @@ void TabHelper::Observe(int type,
   DCHECK(type == content::NOTIFICATION_LOAD_STOP);
   const NavigationController& controller =
       *content::Source<NavigationController>(source).ptr();
-  DCHECK_EQ(controller.GetWebContents(), tab_contents_->web_contents());
+  DCHECK_EQ(controller.GetWebContents(), web_contents());
 
   if (pending_web_app_action_ == UPDATE_SHORTCUT) {
     // Schedule a shortcut update when web application info is available if
diff --git a/chrome/browser/extensions/tab_helper.h b/chrome/browser/extensions/tab_helper.h
index 1703122..f988f83 100644
--- a/chrome/browser/extensions/tab_helper.h
+++ b/chrome/browser/extensions/tab_helper.h
@@ -14,13 +14,13 @@
 #include "chrome/browser/extensions/image_loading_tracker.h"
 #include "chrome/browser/extensions/script_executor.h"
 #include "chrome/browser/extensions/webstore_inline_installer.h"
+#include "chrome/browser/tab_contents/web_contents_user_data.h"
 #include "chrome/common/web_apps.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
-class TabContents;
 struct WebApplicationInfo;
 
 namespace content {
@@ -40,7 +40,8 @@ class TabHelper : public content::WebContentsObserver,
                   public WebstoreInlineInstaller::Delegate,
                   public AppNotifyChannelSetup::Delegate,
                   public base::SupportsWeakPtr<TabHelper>,
-                  public content::NotificationObserver {
+                  public content::NotificationObserver,
+                  public WebContentsUserData<TabHelper> {
  public:
   // Different types of action when web app info is available.
   // OnDidGetApplicationInfo uses this to dispatch calls.
@@ -50,11 +51,9 @@ class TabHelper : public content::WebContentsObserver,
     UPDATE_SHORTCUT   // Update icon for app shortcut.
   };
 
-  explicit TabHelper(TabContents* tab_contents);
+  explicit TabHelper(content::WebContents* web_contents);
   virtual ~TabHelper();
-
-  // Copies the internal state from another TabHelper.
-  void CopyStateFrom(const TabHelper& source);
+  static int kUserDataKey;
 
   void CreateApplicationShortcuts();
   bool CanCreateApplicationShortcuts() const;
@@ -95,10 +94,6 @@ class TabHelper : public content::WebContentsObserver,
   // Extension::EXTENSION_ICON_SMALLISH).
   SkBitmap* GetExtensionAppIcon();
 
-  TabContents* tab_contents() {
-    return tab_contents_;
-  }
-
   content::WebContents* web_contents() const {
     return content::WebContentsObserver::web_contents();
   }
@@ -127,6 +122,9 @@ class TabHelper : public content::WebContentsObserver,
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+  virtual void DidCloneToNewWebContents(
+      content::WebContents* old_web_contents,
+      content::WebContents* new_web_contents) OVERRIDE;
 
   // ExtensionFunctionDispatcher::Delegate overrides.
   virtual extensions::WindowController* GetExtensionWindowController()
@@ -215,8 +213,6 @@ class TabHelper : public content::WebContentsObserver,
 
   content::NotificationRegistrar registrar_;
 
-  TabContents* tab_contents_;
-
   ScriptExecutor script_executor_;
 
   scoped_ptr<LocationBarController> location_bar_controller_;
diff --git a/chrome/browser/sessions/session_service.cc b/chrome/browser/sessions/session_service.cc
index aeb341c..2076bfb 100644
--- a/chrome/browser/sessions/session_service.cc
+++ b/chrome/browser/sessions/session_service.cc
@@ -606,10 +606,12 @@ void SessionService::Observe(int type,
         return;
       SetTabWindow(tab->session_tab_helper()->window_id(),
                    tab->session_tab_helper()->session_id());
-      if (tab->extension_tab_helper()->extension_app()) {
+      extensions::TabHelper* extensions_tab_helper =
+          extensions::TabHelper::FromWebContents(tab->web_contents());
+      if (extensions_tab_helper->extension_app()) {
         SetTabExtensionAppID(tab->session_tab_helper()->window_id(),
             tab->session_tab_helper()->session_id(),
-            tab->extension_tab_helper()->extension_app()->id());
+            extensions_tab_helper->extension_app()->id());
       }
 
       // Record the association between the SessionStorageNamespace and the
@@ -706,12 +708,16 @@ void SessionService::Observe(int type,
     case chrome::NOTIFICATION_TAB_CONTENTS_APPLICATION_EXTENSION_CHANGED: {
       extensions::TabHelper* extension_tab_helper =
           content::Source<extensions::TabHelper>(source).ptr();
-      if (extension_tab_helper->tab_contents()->profile() != profile())
+      if (extension_tab_helper->web_contents()->GetBrowserContext() !=
+              profile()) {
         return;
+      }
       if (extension_tab_helper->extension_app()) {
-        SessionTabHelper* helper =
-            extension_tab_helper->tab_contents()->session_tab_helper();
-        SetTabExtensionAppID(helper->window_id(), helper->session_id(),
+        TabContents* tab_contents =
+            TabContents::FromWebContents(extension_tab_helper->web_contents());
+        SessionTabHelper* helper = tab_contents->session_tab_helper();
+        SetTabExtensionAppID(helper->window_id(),
+                             helper->session_id(),
                              extension_tab_helper->extension_app()->id());
       }
       break;
@@ -1304,11 +1310,13 @@ void SessionService::BuildCommandsForTab(
     commands->push_back(CreatePinnedStateCommand(session_id, true));
   }
 
-  if (tab->extension_tab_helper()->extension_app()) {
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(tab->web_contents());
+  if (extensions_tab_helper->extension_app()) {
     commands->push_back(
         CreateSetTabExtensionAppIDCommand(
             kCommandSetExtensionAppID, session_id.id(),
-            tab->extension_tab_helper()->extension_app()->id()));
+            extensions_tab_helper->extension_app()->id()));
   }
 
   const std::string& ua_override = tab->web_contents()->GetUserAgentOverride();
diff --git a/chrome/browser/sessions/tab_restore_service.cc b/chrome/browser/sessions/tab_restore_service.cc
index d66cc8c..19f5ada 100644
--- a/chrome/browser/sessions/tab_restore_service.cc
+++ b/chrome/browser/sessions/tab_restore_service.cc
@@ -542,7 +542,8 @@ void TabRestoreService::PopulateTab(Tab* tab,
   // tab_contents is NULL in some browser tests.
   if (tab_contents) {
     const extensions::Extension* extension =
-        tab_contents->extension_tab_helper()->extension_app();
+        extensions::TabHelper::FromWebContents(controller->GetWebContents())->
+            extension_app();
     if (extension)
       tab->extension_app_id = extension->id();
   }
diff --git a/chrome/browser/sync/glue/session_change_processor.cc b/chrome/browser/sync/glue/session_change_processor.cc
index 815220e..2b98f68 100644
--- a/chrome/browser/sync/glue/session_change_processor.cc
+++ b/chrome/browser/sync/glue/session_change_processor.cc
@@ -181,14 +181,14 @@ void SessionChangeProcessor::Observe(
     case chrome::NOTIFICATION_TAB_CONTENTS_APPLICATION_EXTENSION_CHANGED: {
       extensions::TabHelper* extension_tab_helper =
           content::Source<extensions::TabHelper>(source).ptr();
-      if (!extension_tab_helper ||
-          extension_tab_helper->web_contents()->GetBrowserContext() !=
+      if (extension_tab_helper->web_contents()->GetBrowserContext() !=
               profile_) {
         return;
       }
       if (extension_tab_helper->extension_app()) {
-        modified_tabs.push_back(extension_tab_helper->tab_contents()->
-            synced_tab_delegate());
+        TabContents* tab_contents =
+            TabContents::FromWebContents(extension_tab_helper->web_contents());
+        modified_tabs.push_back(tab_contents->synced_tab_delegate());
       }
       DVLOG(1) << "Received TAB_CONTENTS_APPLICATION_EXTENSION_CHANGED "
                << "for profile " << profile_;
diff --git a/chrome/browser/tab_contents/web_contents_user_data.h b/chrome/browser/tab_contents/web_contents_user_data.h
index 3fe60c2..ba300a9 100644
--- a/chrome/browser/tab_contents/web_contents_user_data.h
+++ b/chrome/browser/tab_contents/web_contents_user_data.h
@@ -38,6 +38,13 @@ class WebContentsUserData : public base::SupportsUserData::Data {
   static T* FromWebContents(content::WebContents* contents) {
     return static_cast<T*>(contents->GetUserData(&T::kUserDataKey));
   }
+
+  // Retrieves the instance of type T that was attached to the specified
+  // WebContents (via CreateForWebContents above) and returns it. If no instance
+  // of the type was attached, returns NULL.
+  static const T* FromWebContents(const content::WebContents* contents) {
+    return static_cast<const T*>(contents->GetUserData(&T::kUserDataKey));
+  }
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_WEB_CONTENTS_USER_DATA_H_
diff --git a/chrome/browser/ui/ash/launcher/browser_launcher_item_controller.cc b/chrome/browser/ui/ash/launcher/browser_launcher_item_controller.cc
index 3ffda1c..5e3e64c 100644
--- a/chrome/browser/ui/ash/launcher/browser_launcher_item_controller.cc
+++ b/chrome/browser/ui/ash/launcher/browser_launcher_item_controller.cc
@@ -251,11 +251,11 @@ void BrowserLauncherItemController::UpdateLauncher(TabContents* tab) {
           new LauncherFaviconLoader(this, tab->web_contents()));
     }
     // Update the icon for extension panels.
+    extensions::TabHelper* extensions_tab_helper =
+        extensions::TabHelper::FromWebContents(tab->web_contents());
     SkBitmap new_image = favicon_loader_->GetFavicon();
-    if (new_image.isNull() &&
-        tab->extension_tab_helper()->GetExtensionAppIcon()) {
-      new_image = *tab->extension_tab_helper()->GetExtensionAppIcon();
-    }
+    if (new_image.isNull() && extensions_tab_helper->GetExtensionAppIcon())
+      new_image = *extensions_tab_helper->GetExtensionAppIcon();
     // Only update the icon if we have a new image, or none has been set yet.
     // This avoids flickering to an empty image when a pinned app is opened.
     if (!new_image.isNull())
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index c0f6a9f..d44901a 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -800,7 +800,9 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, TabClosingWhenRemovingExtension) {
 
   TabContents* app_contents = chrome::TabContentsFactory(
       browser()->profile(), NULL, MSG_ROUTING_NONE, NULL);
-  app_contents->extension_tab_helper()->SetExtensionApp(extension_app);
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(app_contents->web_contents());
+  extensions_tab_helper->SetExtensionApp(extension_app);
 
   model->AddTabContents(app_contents, 0, content::PageTransitionFromInt(0),
                         TabStripModel::ADD_NONE);
@@ -919,7 +921,9 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, RestorePinnedTabs) {
   ui_test_utils::NavigateToURL(browser(), url);
   TabContents* app_contents = chrome::TabContentsFactory(
       browser()->profile(), NULL, MSG_ROUTING_NONE, NULL);
-  app_contents->extension_tab_helper()->SetExtensionApp(extension_app);
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(app_contents->web_contents());
+  extensions_tab_helper->SetExtensionApp(extension_app);
   model->AddTabContents(app_contents, 0, content::PageTransitionFromInt(0),
                         TabStripModel::ADD_NONE);
   model->SetTabPinned(0, true);
@@ -975,8 +979,9 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, RestorePinnedTabs) {
       new_model->GetTabContentsAt(2)->web_contents()->GetURL());
 
   EXPECT_TRUE(
-      new_model->GetTabContentsAt(0)->extension_tab_helper()->extension_app() ==
-          extension_app);
+      extensions::TabHelper::FromWebContents(
+          new_model->GetTabContentsAt(0)->web_contents())->
+              extension_app() == extension_app);
 }
 #endif  // !defined(OS_CHROMEOS)
 
@@ -1007,10 +1012,11 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, OpenAppWindowLikeNtp) {
                                        NEW_WINDOW));
   ASSERT_TRUE(app_window);
 
-  // Apps launched in a window from the NTP do not have extension_app set in
-  // tab contents.
-  TabContents* tab_contents = TabContents::FromWebContents(app_window);
-  EXPECT_FALSE(tab_contents->extension_tab_helper()->extension_app());
+  // Apps launched in a window from the NTP have an extensions tab helper but
+  // do not have extension_app set in it.
+  ASSERT_TRUE(extensions::TabHelper::FromWebContents(app_window));
+  EXPECT_FALSE(
+      extensions::TabHelper::FromWebContents(app_window)->extension_app());
   EXPECT_EQ(extension_app->GetFullLaunchURL(), app_window->GetURL());
 
   // The launch should have created a new browser.
diff --git a/chrome/browser/ui/browser_commands.cc b/chrome/browser/ui/browser_commands.cc
index 3d88794..4ebcfdd 100644
--- a/chrome/browser/ui/browser_commands.cc
+++ b/chrome/browser/ui/browser_commands.cc
@@ -972,12 +972,12 @@ bool CanViewSource(const Browser* browser) {
 
 void CreateApplicationShortcuts(Browser* browser) {
   content::RecordAction(UserMetricsAction("CreateShortcut"));
-  GetActiveTabContents(browser)->extension_tab_helper()->
+  extensions::TabHelper::FromWebContents(GetActiveWebContents(browser))->
       CreateApplicationShortcuts();
 }
 
 bool CanCreateApplicationShortcuts(const Browser* browser) {
-  return GetActiveTabContents(browser)->extension_tab_helper()->
+  return extensions::TabHelper::FromWebContents(GetActiveWebContents(browser))->
       CanCreateApplicationShortcuts();
 }
 
diff --git a/chrome/browser/ui/browser_navigator.cc b/chrome/browser/ui/browser_navigator.cc
index 6049b93..efaadee 100644
--- a/chrome/browser/ui/browser_navigator.cc
+++ b/chrome/browser/ui/browser_navigator.cc
@@ -132,11 +132,14 @@ Browser* GetBrowserForDisposition(chrome::NavigateParams* params) {
             params->extension_app_id);
       } else if (!params->browser->app_name().empty()) {
         app_name = params->browser->app_name();
-      } else if (params->source_contents &&
-                 params->source_contents->extension_tab_helper()->is_app()) {
-        app_name = web_app::GenerateApplicationNameFromExtensionId(
-            params->source_contents->extension_tab_helper()->
-                extension_app()->id());
+      } else if (params->source_contents) {
+        extensions::TabHelper* extensions_tab_helper =
+            extensions::TabHelper::FromWebContents(
+                params->source_contents->web_contents());
+        if (extensions_tab_helper->is_app()) {
+          app_name = web_app::GenerateApplicationNameFromExtensionId(
+              extensions_tab_helper->extension_app()->id());
+        }
       }
       if (app_name.empty()) {
         Browser::CreateParams browser_params(Browser::TYPE_POPUP, profile);
@@ -494,8 +497,9 @@ void Navigate(NavigateParams* params) {
       // This function takes ownership of |params->target_contents| until it
       // is added to a TabStripModel.
       target_contents_owner.TakeOwnership();
-      params->target_contents->extension_tab_helper()->
-          SetExtensionAppById(params->extension_app_id);
+      extensions::TabHelper::FromWebContents(
+          params->target_contents->web_contents())->
+              SetExtensionAppById(params->extension_app_id);
       // TODO(sky): figure out why this is needed. Without it we seem to get
       // failures in startup tests.
       // By default, content believes it is not hidden.  When adding contents
diff --git a/chrome/browser/ui/browser_tabrestore.cc b/chrome/browser/ui/browser_tabrestore.cc
index 566cb86..4443305 100644
--- a/chrome/browser/ui/browser_tabrestore.cc
+++ b/chrome/browser/ui/browser_tabrestore.cc
@@ -57,7 +57,8 @@ content::WebContents* AddRestoredTab(
       chrome::GetActiveWebContents(browser),
       session_storage_namespace_map);
   WebContents* new_tab = tab_contents->web_contents();
-  tab_contents->extension_tab_helper()->SetExtensionAppById(extension_app_id);
+  extensions::TabHelper::FromWebContents(new_tab)->
+      SetExtensionAppById(extension_app_id);
   std::vector<NavigationEntry*> entries;
   TabNavigation::CreateNavigationEntriesFromTabNavigations(
       browser->profile(), navigations, &entries);
@@ -118,8 +119,9 @@ void ReplaceRestoredTab(
       MSG_ROUTING_NONE,
       GetActiveWebContents(browser),
       session_storage_namespace_map);
-  tab_contents->extension_tab_helper()->SetExtensionAppById(extension_app_id);
   WebContents* replacement = tab_contents->web_contents();
+  extensions::TabHelper::FromWebContents(replacement)->
+      SetExtensionAppById(extension_app_id);
   replacement->SetUserAgentOverride(user_agent_override);
   std::vector<NavigationEntry*> entries;
   TabNavigation::CreateNavigationEntriesFromTabNavigations(
diff --git a/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.mm b/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.mm
index 92309f5..bfa7929 100644
--- a/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.mm
+++ b/chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.mm
@@ -624,8 +624,8 @@ void LocationBarViewMac::RefreshPageActionDecorations() {
   }
 
   std::vector<ExtensionAction*> new_page_actions =
-      tab_contents->extension_tab_helper()->location_bar_controller()->
-          GetCurrentActions();
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+          location_bar_controller()->GetCurrentActions();
 
   if (new_page_actions != page_actions_) {
     page_actions_.swap(new_page_actions);
diff --git a/chrome/browser/ui/cocoa/location_bar/page_action_decoration.mm b/chrome/browser/ui/cocoa/location_bar/page_action_decoration.mm
index 689687d..7f86cde 100644
--- a/chrome/browser/ui/cocoa/location_bar/page_action_decoration.mm
+++ b/chrome/browser/ui/cocoa/location_bar/page_action_decoration.mm
@@ -113,7 +113,8 @@ bool PageActionDecoration::ActivatePageAction(NSRect frame) {
   }
 
   LocationBarController* controller =
-      tab_contents->extension_tab_helper()->location_bar_controller();
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+          location_bar_controller();
 
   // 1 is left click.
   switch (controller->OnClicked(page_action_->extension_id(), 1)) {
diff --git a/chrome/browser/ui/cocoa/tabpose_window.mm b/chrome/browser/ui/cocoa/tabpose_window.mm
index 056519a..7bd20f1 100644
--- a/chrome/browser/ui/cocoa/tabpose_window.mm
+++ b/chrome/browser/ui/cocoa/tabpose_window.mm
@@ -457,8 +457,10 @@ NSRect Tile::GetFaviconStartRectRelativeTo(const Tile& tile) const {
 }
 
 NSImage* Tile::favicon() const {
-  if (contents_->extension_tab_helper()->is_app()) {
-    SkBitmap* bitmap = contents_->extension_tab_helper()->GetExtensionAppIcon();
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(contents_->web_contents());
+  if (extensions_tab_helper->is_app()) {
+    SkBitmap* bitmap = extensions_tab_helper->GetExtensionAppIcon();
     if (bitmap)
       return gfx::SkBitmapToNSImage(*bitmap);
   }
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
index 2c1c908..b41d4c6 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
@@ -1418,13 +1418,15 @@ private:
 // A helper routine for creating an NSImageView to hold the favicon or app icon
 // for |contents|.
 - (NSImageView*)iconImageViewForContents:(TabContents*)contents {
-  BOOL isApp = contents->extension_tab_helper()->is_app();
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(contents->web_contents());
+  BOOL isApp = extensions_tab_helper->is_app();
   NSImage* image = nil;
   // Favicons come from the renderer, and the renderer draws everything in the
   // system color space.
   CGColorSpaceRef colorSpace = base::mac::GetSystemColorSpace();
   if (isApp) {
-    SkBitmap* icon = contents->extension_tab_helper()->GetExtensionAppIcon();
+    SkBitmap* icon = extensions_tab_helper->GetExtensionAppIcon();
     if (icon)
       image = gfx::SkBitmapToNSImageWithColorSpace(*icon, colorSpace);
   } else {
diff --git a/chrome/browser/ui/extensions/application_launch.cc b/chrome/browser/ui/extensions/application_launch.cc
index 9af96e0..0e1e4e9 100644
--- a/chrome/browser/ui/extensions/application_launch.cc
+++ b/chrome/browser/ui/extensions/application_launch.cc
@@ -282,14 +282,13 @@ WebContents* OpenAppShortcutWindow(Profile* profile,
   if (!tab)
     return NULL;
 
-  TabContents* tab_contents = TabContents::FromWebContents(tab);
   // Set UPDATE_SHORTCUT as the pending web app action. This action is picked
   // up in LoadingStateChanged to schedule a GetApplicationInfo. And when
   // the web app info is available, extensions::TabHelper notifies Browser via
   // OnDidGetApplicationInfo, which calls
   // web_app::UpdateShortcutForTabContents when it sees UPDATE_SHORTCUT as
   // pending web app action.
-  tab_contents->extension_tab_helper()->set_pending_web_app_action(
+  extensions::TabHelper::FromWebContents(tab)->set_pending_web_app_action(
       extensions::TabHelper::UPDATE_SHORTCUT);
 
   return tab;
diff --git a/chrome/browser/ui/gtk/location_bar_view_gtk.cc b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
index bb99898..24b7f33 100644
--- a/chrome/browser/ui/gtk/location_bar_view_gtk.cc
+++ b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
@@ -955,10 +955,11 @@ void LocationBarViewGtk::UpdateContentSettingsIcons() {
 void LocationBarViewGtk::UpdatePageActions() {
   std::vector<ExtensionAction*> new_page_actions;
 
-  TabContents* tab_contents = GetTabContents();
-  if (tab_contents) {
+  WebContents* contents = GetWebContents();
+  if (contents) {
     LocationBarController* location_bar_controller =
-        tab_contents->extension_tab_helper()->location_bar_controller();
+        extensions::TabHelper::FromWebContents(contents)->
+            location_bar_controller();
     new_page_actions = location_bar_controller->GetCurrentActions();
   }
 
@@ -980,7 +981,6 @@ void LocationBarViewGtk::UpdatePageActions() {
         content::NotificationService::NoDetails());
   }
 
-  WebContents* contents = GetWebContents();
   if (!page_action_views_.empty() && contents) {
     GURL url = chrome::GetActiveWebContents(browser())->GetURL();
 
@@ -2031,7 +2031,8 @@ gboolean LocationBarViewGtk::PageActionViewGtk::OnButtonPressed(
     return TRUE;
 
   LocationBarController* controller =
-      tab_contents->extension_tab_helper()->location_bar_controller();
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+          location_bar_controller();
 
   switch (controller->OnClicked(extension->id(), event->button)) {
     case LocationBarController::ACTION_NONE:
diff --git a/chrome/browser/ui/gtk/tabs/dragged_view_gtk.cc b/chrome/browser/ui/gtk/tabs/dragged_view_gtk.cc
index dc69869..5a31b22 100644
--- a/chrome/browser/ui/gtk/tabs/dragged_view_gtk.cc
+++ b/chrome/browser/ui/gtk/tabs/dragged_view_gtk.cc
@@ -71,11 +71,10 @@ DraggedViewGtk::DraggedViewGtk(DragData* drag_data,
   }
 
   for (size_t i = 0; i < drag_data_->size(); i++) {
-    TabContents* tab_contents = TabContents::FromWebContents(
-        drag_data_->get(i)->contents_->web_contents());
+    WebContents* web_contents = drag_data_->get(i)->contents_->web_contents();
     renderers_[i]->UpdateData(
-        drag_data_->get(i)->contents_->web_contents(),
-        tab_contents->extension_tab_helper()->is_app(),
+        web_contents,
+        extensions::TabHelper::FromWebContents(web_contents)->is_app(),
         false); // loading_only
     renderers_[i]->set_is_active(
         static_cast<int>(i) == drag_data_->source_tab_index());
diff --git a/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc b/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
index 7b9dcbd..0b201ae 100644
--- a/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
+++ b/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
@@ -333,7 +333,7 @@ void TabRendererGtk::UpdateData(WebContents* contents,
     data_.crashed = contents->IsCrashed();
 
     SkBitmap* app_icon =
-        tab_contents->extension_tab_helper()->GetExtensionAppIcon();
+        extensions::TabHelper::FromWebContents(contents)->GetExtensionAppIcon();
     if (app_icon) {
       data_.favicon = *app_icon;
     } else {
diff --git a/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc b/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
index 59474bf..400c5b2 100644
--- a/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
+++ b/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
@@ -37,14 +37,15 @@ Profile* TabContentsSyncedTabDelegate::profile() const {
 }
 
 bool TabContentsSyncedTabDelegate::HasExtensionAppId() const {
-  return (tab_contents_->extension_tab_helper() &&
-      tab_contents_->extension_tab_helper()->extension_app());
+  return !!(extensions::TabHelper::FromWebContents(
+      tab_contents_->web_contents())->extension_app());
 }
 
 const std::string& TabContentsSyncedTabDelegate::GetExtensionAppId()
     const {
   DCHECK(HasExtensionAppId());
-  return tab_contents_->extension_tab_helper()->extension_app()->id();
+  return extensions::TabHelper::FromWebContents(tab_contents_->web_contents())->
+      extension_app()->id();
 }
 
 int TabContentsSyncedTabDelegate::GetCurrentEntryIndex() const {
diff --git a/chrome/browser/ui/tab_contents/tab_contents.cc b/chrome/browser/ui/tab_contents/tab_contents.cc
index 539eba3..f74d387 100644
--- a/chrome/browser/ui/tab_contents/tab_contents.cc
+++ b/chrome/browser/ui/tab_contents/tab_contents.cc
@@ -134,7 +134,7 @@ TabContents::TabContents(WebContents* contents)
 #endif
   constrained_window_tab_helper_.reset(new ConstrainedWindowTabHelper(this));
   core_tab_helper_.reset(new CoreTabHelper(contents));
-  extension_tab_helper_.reset(new extensions::TabHelper(this));
+  extensions::TabHelper::CreateForWebContents(contents);
   favicon_tab_helper_.reset(new FaviconTabHelper(contents));
   find_tab_helper_.reset(new FindTabHelper(contents));
   history_tab_helper_.reset(new HistoryTabHelper(contents));
@@ -218,13 +218,7 @@ TabContents::~TabContents() {
 
 TabContents* TabContents::Clone() {
   WebContents* new_web_contents = web_contents()->Clone();
-  TabContents* new_tab_contents = new TabContents(new_web_contents);
-
-  // TODO(avi): Can we generalize this so that knowledge of the functionings of
-  // the tab helpers isn't required here?
-  new_tab_contents->extension_tab_helper()->CopyStateFrom(
-      *extension_tab_helper_.get());
-  return new_tab_contents;
+  return new TabContents(new_web_contents);
 }
 
 // static
diff --git a/chrome/browser/ui/tab_contents/tab_contents.h b/chrome/browser/ui/tab_contents/tab_contents.h
index 4c5b5a0..2cf02d1 100644
--- a/chrome/browser/ui/tab_contents/tab_contents.h
+++ b/chrome/browser/ui/tab_contents/tab_contents.h
@@ -106,7 +106,6 @@ class WebUILoginView;
 }
 
 namespace extensions {
-class TabHelper;
 class WebAuthFlow;
 class WebNavigationTabObserver;
 }
@@ -239,14 +238,6 @@ class TabContents : public content::WebContentsObserver {
 
   CoreTabHelper* core_tab_helper() { return core_tab_helper_.get(); }
 
-  extensions::TabHelper* extension_tab_helper() {
-    return extension_tab_helper_.get();
-  }
-
-  const extensions::TabHelper* extension_tab_helper() const {
-    return extension_tab_helper_.get();
-  }
-
   FaviconTabHelper* favicon_tab_helper() { return favicon_tab_helper_.get(); }
   FindTabHelper* find_tab_helper() { return find_tab_helper_.get(); }
   HistoryTabHelper* history_tab_helper() { return history_tab_helper_.get(); }
@@ -355,7 +346,6 @@ class TabContents : public content::WebContentsObserver {
 #endif
   scoped_ptr<ConstrainedWindowTabHelper> constrained_window_tab_helper_;
   scoped_ptr<CoreTabHelper> core_tab_helper_;
-  scoped_ptr<extensions::TabHelper> extension_tab_helper_;
   scoped_ptr<FaviconTabHelper> favicon_tab_helper_;
   scoped_ptr<FindTabHelper> find_tab_helper_;
   scoped_ptr<HistoryTabHelper> history_tab_helper_;
diff --git a/chrome/browser/ui/tabs/pinned_tab_codec.cc b/chrome/browser/ui/tabs/pinned_tab_codec.cc
index 3ff361dc..45895213 100644
--- a/chrome/browser/ui/tabs/pinned_tab_codec.cc
+++ b/chrome/browser/ui/tabs/pinned_tab_codec.cc
@@ -52,22 +52,22 @@ static void EncodePinnedTab(TabStripModel* model,
                             ListValue* values) {
   scoped_ptr<DictionaryValue> value(new DictionaryValue());
 
-  TabContents* tab_contents = model->GetTabContentsAt(index);
+  content::WebContents* web_contents =
+      model->GetTabContentsAt(index)->web_contents();
   if (model->IsAppTab(index)) {
     const extensions::Extension* extension =
-        tab_contents->extension_tab_helper()->extension_app();
+        extensions::TabHelper::FromWebContents(web_contents)->extension_app();
     DCHECK(extension);
     value->SetString(kAppID, extension->id());
-    // For apps we use the launch url. We do this for the following reason:
-    // . the user is effectively restarting the app, so that returning them to
-    //   the app's launch page seems closest to what they expect.
+    // For apps we use the launch url. We do this because the user is
+    // effectively restarting the app, so returning them to the app's launch
+    // page seems closest to what they expect.
     value->SetString(kURL, extension->GetFullLaunchURL().spec());
     values->Append(value.release());
   } else {
-    NavigationEntry* entry =
-        tab_contents->web_contents()->GetController().GetActiveEntry();
-    if (!entry && tab_contents->web_contents()->GetController().GetEntryCount())
-      entry = tab_contents->web_contents()->GetController().GetEntryAtIndex(0);
+    NavigationEntry* entry = web_contents->GetController().GetActiveEntry();
+    if (!entry && web_contents->GetController().GetEntryCount())
+      entry = web_contents->GetController().GetEntryAtIndex(0);
     if (entry) {
       value->SetString(kURL, entry->GetURL().spec());
       values->Append(value.release());
diff --git a/chrome/browser/ui/tabs/tab_strip_model.cc b/chrome/browser/ui/tabs/tab_strip_model.cc
index 3885ee8..c622f87 100644
--- a/chrome/browser/ui/tabs/tab_strip_model.cc
+++ b/chrome/browser/ui/tabs/tab_strip_model.cc
@@ -120,8 +120,9 @@ void TabStripModel::InsertTabContentsAt(int index,
                                         int add_types) {
   bool active = add_types & ADD_ACTIVE;
   // Force app tabs to be pinned.
-  bool pin =
-      contents->extension_tab_helper()->is_app() || add_types & ADD_PINNED;
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(contents->web_contents());
+  bool pin = extensions_tab_helper->is_app() || add_types & ADD_PINNED;
   index = ConstrainInsertionIndex(index, pin);
 
   // In tab dragging situations, if the last tab in the window was detached
@@ -565,8 +566,8 @@ bool TabStripModel::IsMiniTab(int index) const {
 }
 
 bool TabStripModel::IsAppTab(int index) const {
-  TabContents* contents = GetTabContentsAt(index);
-  return contents && contents->extension_tab_helper()->is_app();
+  WebContents* contents = GetTabContentsAt(index)->web_contents();
+  return contents && extensions::TabHelper::FromWebContents(contents)->is_app();
 }
 
 bool TabStripModel::IsTabBlocked(int index) const {
@@ -999,7 +1000,8 @@ void TabStripModel::Observe(int type,
       // Iterate backwards as we may remove items while iterating.
       for (int i = count() - 1; i >= 0; i--) {
         TabContents* contents = GetTabContentsAt(i);
-        if (contents->extension_tab_helper()->extension_app() == extension) {
+        if (extensions::TabHelper::FromWebContents(contents->web_contents())->
+              extension_app() == extension) {
           // The extension an app tab was created from has been nuked. Delete
           // the WebContents. Deleting a WebContents results in a notification
           // of type NOTIFICATION_WEB_CONTENTS_DESTROYED; we do the necessary
diff --git a/chrome/browser/ui/tabs/tab_strip_model_unittest.cc b/chrome/browser/ui/tabs/tab_strip_model_unittest.cc
index e5e9b83..17b1b1d 100644
--- a/chrome/browser/ui/tabs/tab_strip_model_unittest.cc
+++ b/chrome/browser/ui/tabs/tab_strip_model_unittest.cc
@@ -1832,9 +1832,11 @@ TEST_F(TabStripModelTest, Apps) {
                         &error));
   extension_app->launch_web_url_ = "http://www.google.com";
   TabContents* contents1 = CreateTabContents();
-  contents1->extension_tab_helper()->SetExtensionApp(extension_app);
+  extensions::TabHelper::FromWebContents(contents1->web_contents())->
+      SetExtensionApp(extension_app);
   TabContents* contents2 = CreateTabContents();
-  contents2->extension_tab_helper()->SetExtensionApp(extension_app);
+  extensions::TabHelper::FromWebContents(contents2->web_contents())->
+      SetExtensionApp(extension_app);
   TabContents* contents3 = CreateTabContents();
 
   SetID(contents1->web_contents(), 1);
diff --git a/chrome/browser/ui/views/create_application_shortcut_view.cc b/chrome/browser/ui/views/create_application_shortcut_view.cc
index 8c2b8d6..1642c5e 100644
--- a/chrome/browser/ui/views/create_application_shortcut_view.cc
+++ b/chrome/browser/ui/views/create_application_shortcut_view.cc
@@ -422,7 +422,8 @@ CreateUrlApplicationShortcutView::CreateUrlApplicationShortcutView(
 
   web_app::GetShortcutInfoForTab(tab_contents_, &shortcut_info_);
   const WebApplicationInfo& app_info =
-      tab_contents_->extension_tab_helper()->web_app_info();
+      extensions::TabHelper::FromWebContents(tab_contents_->web_contents())->
+          web_app_info();
   if (!app_info.icons.empty()) {
     web_app::GetIconsInfo(app_info, &unprocessed_icons_);
     FetchIcon();
@@ -440,9 +441,10 @@ bool CreateUrlApplicationShortcutView::Accept() {
   if (!CreateApplicationShortcutView::Accept())
     return false;
 
-  tab_contents_->extension_tab_helper()->SetAppIcon(
-      shortcut_info_.favicon.IsEmpty() ? SkBitmap() :
-                                         *shortcut_info_.favicon.ToSkBitmap());
+  extensions::TabHelper::FromWebContents(tab_contents_->web_contents())->
+      SetAppIcon(shortcut_info_.favicon.IsEmpty()
+          ? SkBitmap()
+          : *shortcut_info_.favicon.ToSkBitmap());
   Browser* browser =
       browser::FindBrowserWithWebContents(tab_contents_->web_contents());
   if (browser)
diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index b10999d..4a09035 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -1535,9 +1535,11 @@ bool BrowserView::ShouldShowWindowTitle() const {
 
 gfx::ImageSkia BrowserView::GetWindowAppIcon() {
   if (browser_->is_app()) {
-    TabContents* contents = chrome::GetActiveTabContents(browser_.get());
-    if (contents && contents->extension_tab_helper()->GetExtensionAppIcon())
-      return *contents->extension_tab_helper()->GetExtensionAppIcon();
+    WebContents* contents = chrome::GetActiveWebContents(browser_.get());
+    extensions::TabHelper* extensions_tab_helper =
+        contents ? extensions::TabHelper::FromWebContents(contents) : NULL;
+    if (extensions_tab_helper && extensions_tab_helper->GetExtensionAppIcon())
+      return *extensions_tab_helper->GetExtensionAppIcon();
   }
 
   return GetWindowIcon();
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 0422245..b38697c 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.cc
@@ -1149,10 +1149,12 @@ void LocationBarView::RefreshPageActionViews() {
 
   std::vector<ExtensionAction*> new_page_actions;
 
-  TabContents* tab_contents = GetTabContents();
-  if (tab_contents) {
+  WebContents* contents = GetWebContentsFromDelegate(delegate_);
+  if (contents) {
+    extensions::TabHelper* extensions_tab_helper =
+        extensions::TabHelper::FromWebContents(contents);
     extensions::LocationBarController* controller =
-        tab_contents->extension_tab_helper()->location_bar_controller();
+        extensions_tab_helper->location_bar_controller();
     new_page_actions = controller->GetCurrentActions();
   }
 
@@ -1178,7 +1180,6 @@ void LocationBarView::RefreshPageActionViews() {
     }
   }
 
-  WebContents* contents = GetWebContentsFromDelegate(delegate_);
   if (!page_action_views_.empty() && contents) {
     Browser* browser = browser::FindBrowserWithWebContents(contents);
     GURL url = chrome::GetActiveWebContents(browser)->GetURL();
diff --git a/chrome/browser/ui/views/location_bar/page_action_image_view.cc b/chrome/browser/ui/views/location_bar/page_action_image_view.cc
index 3b5278f..3e5fdbb 100644
--- a/chrome/browser/ui/views/location_bar/page_action_image_view.cc
+++ b/chrome/browser/ui/views/location_bar/page_action_image_view.cc
@@ -131,8 +131,10 @@ void PageActionImageView::ExecuteAction(int button) {
   if (!tab_contents)
     return;
 
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents());
   LocationBarController* controller =
-      tab_contents->extension_tab_helper()->location_bar_controller();
+      extensions_tab_helper->location_bar_controller();
 
   // 1 is left click.
   switch (controller->OnClicked(page_action_->extension_id(), 1)) {
diff --git a/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc b/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
index 7a82d373..d51d48a 100644
--- a/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
+++ b/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
@@ -526,7 +526,7 @@ void BrowserTabStripController::SetTabRendererDataFromModel(
   data->show_icon = tab_contents->favicon_tab_helper()->ShouldDisplayFavicon();
   data->mini = model_->IsMiniTab(model_index);
   data->blocked = model_->IsTabBlocked(model_index);
-  data->app = tab_contents->extension_tab_helper()->is_app();
+  data->app = extensions::TabHelper::FromWebContents(contents)->is_app();
   data->mode = browser_->search_model()->mode().mode;
   // Get current gradient background animation to paint.
   data->gradient_background_opacity = browser_->search_delegate()->
diff --git a/chrome/browser/ui/web_applications/web_app_ui.cc b/chrome/browser/ui/web_applications/web_app_ui.cc
index 85285d3..a3ce59e 100644
--- a/chrome/browser/ui/web_applications/web_app_ui.cc
+++ b/chrome/browser/ui/web_applications/web_app_ui.cc
@@ -98,8 +98,10 @@ class UpdateShortcutWorker : public content::NotificationObserver {
 UpdateShortcutWorker::UpdateShortcutWorker(TabContents* tab_contents)
     : tab_contents_(tab_contents),
       profile_path_(tab_contents->profile()->GetPath()) {
+  extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents());
   web_app::GetShortcutInfoForTab(tab_contents_, &shortcut_info_);
-  web_app::GetIconsInfo(tab_contents_->extension_tab_helper()->web_app_info(),
+  web_app::GetIconsInfo(extensions_tab_helper->web_app_info(),
                         &unprocessed_icons_);
   file_name_ = web_app::internals::GetSanitizedFileName(shortcut_info_.title);
 
@@ -164,7 +166,9 @@ void UpdateShortcutWorker::OnIconDownloaded(int download_id,
   if (!errored && !image.isNull()) {
     // Update icon with download image and update shortcut.
     shortcut_info_.favicon = gfx::Image(image);
-    tab_contents_->extension_tab_helper()->SetAppIcon(image);
+    extensions::TabHelper* extensions_tab_helper =
+        extensions::TabHelper::FromWebContents(tab_contents_->web_contents());
+    extensions_tab_helper->SetAppIcon(image);
     UpdateShortcuts();
   } else {
     // Try the next icon otherwise.
@@ -303,8 +307,9 @@ void GetShortcutInfoForTab(TabContents* tab_contents,
   DCHECK(info);  // Must provide a valid info.
   const WebContents* web_contents = tab_contents->web_contents();
 
-  const WebApplicationInfo& app_info =
-      tab_contents->extension_tab_helper()->web_app_info();
+  const extensions::TabHelper* extensions_tab_helper =
+      extensions::TabHelper::FromWebContents(web_contents);
+  const WebApplicationInfo& app_info = extensions_tab_helper->web_app_info();
 
   info->url = app_info.app_url.is_empty() ? web_contents->GetURL() :
                                             app_info.app_url;