Implement a NTP resource cache. Instead of re-generating the

HTML for the NTP each time, keep a cached copy as part of the
profile.

- This changes the handling of StartDataRequest to always happen
on the UI thread since it needs to use the Profile.  Previously
we would generate on the UI thread then handle all the requests
on the IO thread.
- first_view_ got changed into a static bool.  I also removed it
from being added to the json because it didn't appear to be used
anywhere.
- Merge the incognito and regular handler into one since I added
that as a flag to the request in a previous change.

I plan to add the CSS to NTPResourceCache next.

BUG=23120

Review URL: http://codereview.chromium.org/399055

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32520 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 401 insertions, 377 deletions

diff --git a/chrome/browser/dom_ui/new_tab_ui.cc b/chrome/browser/dom_ui/new_tab_ui.cc
index 7c8c507..b11d7b4 100644
--- a/chrome/browser/dom_ui/new_tab_ui.cc
+++ b/chrome/browser/dom_ui/new_tab_ui.cc
@@ -8,21 +8,17 @@
 
 #include <set>
 
-#include "app/animation.h"
 #include "app/l10n_util.h"
-#include "app/resource_bundle.h"
-#include "app/theme_provider.h"
 #include "base/command_line.h"
-#include "base/file_util.h"
 #include "base/histogram.h"
 #include "base/singleton.h"
-#include "base/string_piece.h"
 #include "base/thread.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/dom_ui/dom_ui_theme_source.h"
 #include "chrome/browser/dom_ui/most_visited_handler.h"
 #include "chrome/browser/dom_ui/new_tab_page_sync_handler.h"
+#include "chrome/browser/dom_ui/ntp_resource_cache.h"
 #include "chrome/browser/dom_ui/shown_sections_handler.h"
 #include "chrome/browser/dom_ui/tips_handler.h"
 #include "chrome/browser/metrics/user_metrics.h"
@@ -32,18 +28,12 @@
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/sessions/tab_restore_service.h"
 #include "chrome/browser/sync/profile_sync_service.h"
-#include "chrome/browser/user_data_manager.h"
 #include "chrome/common/chrome_switches.h"
-#include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/pref_service.h"
 #include "chrome/common/url_constants.h"
-#include "grit/browser_resources.h"
-#include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
-#include "grit/locale_settings.h"
-#include "grit/theme_resources.h"
 
 namespace {
 
@@ -119,87 +109,6 @@ class PaintTimer : public RenderWidgetHost::PaintObserver {
   DISALLOW_COPY_AND_ASSIGN(PaintTimer);
 };
 
-
-///////////////////////////////////////////////////////////////////////////////
-// IncognitoTabHTMLSource
-
-class IncognitoTabHTMLSource : public ChromeURLDataManager::DataSource {
- public:
-  // Creates our datasource and registers initial state of the bookmark bar.
-  explicit IncognitoTabHTMLSource(bool bookmark_bar_attached);
-
-  // Called when the network layer has requested a resource underneath
-  // the path we registered.
-  virtual void StartDataRequest(const std::string& path,
-                                bool is_off_the_record,
-                                int request_id);
-
-  virtual std::string GetMimeType(const std::string&) const {
-    return "text/html";
-  }
-
-  virtual MessageLoop* MessageLoopForRequestPath(const std::string& path)
-      const {
-    // IncognitoTabHTMLSource does all of the operations that need to be on
-    // the UI thread from InitFullHTML, called by the constructor.  It is safe
-    // to call StartDataRequest from any thread, so return NULL.
-    return NULL;
-  }
-
- private:
-  ~IncognitoTabHTMLSource() {}
-
-  // Populate full_html_.  This must be called from the UI thread because it
-  // involves profile access.
-  //
-  // A new IncognitoTabHTMLSource object is used for each incognito tab page
-  // instance and each reload of an existing incognito tab page, so there is
-  // no concern about cached data becoming stale.
-  void InitFullHTML();
-
-  // The content to be served by StartDataRequest, stored by InitFullHTML.
-  std::string full_html_;
-
-  bool bookmark_bar_attached_;
-
-  DISALLOW_COPY_AND_ASSIGN(IncognitoTabHTMLSource);
-};
-
-IncognitoTabHTMLSource::IncognitoTabHTMLSource(bool bookmark_bar_attached)
-    : DataSource(chrome::kChromeUINewTabHost, MessageLoop::current()),
-      bookmark_bar_attached_(bookmark_bar_attached) {
-  InitFullHTML();
-}
-
-void IncognitoTabHTMLSource::StartDataRequest(const std::string& path,
-    bool is_off_the_record, int request_id) {
-  scoped_refptr<RefCountedBytes> html_bytes(new RefCountedBytes);
-  html_bytes->data.resize(full_html_.size());
-  std::copy(full_html_.begin(), full_html_.end(), html_bytes->data.begin());
-
-  SendResponse(request_id, html_bytes);
-}
-
-void IncognitoTabHTMLSource::InitFullHTML() {
-  DictionaryValue localized_strings;
-  localized_strings.SetString(L"title",
-      l10n_util::GetString(IDS_NEW_TAB_TITLE));
-  localized_strings.SetString(L"content",
-      l10n_util::GetStringF(IDS_NEW_TAB_OTR_MESSAGE,
-          l10n_util::GetString(IDS_LEARN_MORE_INCOGNITO_URL)));
-  localized_strings.SetString(L"bookmarkbarattached",
-      bookmark_bar_attached_ ? "true" : "false");
-
-  SetFontAndTextDirection(&localized_strings);
-
-  static const base::StringPiece incognito_tab_html(
-      ResourceBundle::GetSharedInstance().GetRawDataResource(
-          IDR_INCOGNITO_TAB_HTML));
-
-  full_html_ = jstemplate_builder::GetI18nTemplateHtml(incognito_tab_html,
-                                                       &localized_strings);
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 // PromotionalMessageHandler
 
@@ -554,9 +463,7 @@ void NewTabPageSetHomePageHandler::HandleSetHomePage(
 // NewTabUI
 
 NewTabUI::NewTabUI(TabContents* contents)
-    : DOMUI(contents),
-      motd_message_id_(0),
-      incognito_(false) {
+    : DOMUI(contents) {
   // Override some options on the DOM UI.
   hide_favicon_ = true;
   force_bookmark_bar_visible_ = true;
@@ -574,18 +481,20 @@ NewTabUI::NewTabUI(TabContents* contents)
     NewTabHTMLSource::set_first_run(false);
 
   InitializeCSSCaches();
-  if (GetProfile()->IsOffTheRecord()) {
-    incognito_ = true;
-
-    IncognitoTabHTMLSource* html_source = new IncognitoTabHTMLSource(
-        GetProfile()->GetPrefs()->GetBoolean(prefs::kShowBookmarkBar));
-    ChromeThread::PostTask(
-        ChromeThread::IO, FROM_HERE,
-        NewRunnableMethod(
-            Singleton<ChromeURLDataManager>::get(),
-            &ChromeURLDataManager::AddDataSource,
-            html_source));
-  } else {
+  NewTabHTMLSource* html_source =
+      new NewTabHTMLSource(GetProfile()->GetOriginalProfile());
+  bool posted = ChromeThread::PostTask(
+      ChromeThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          Singleton<ChromeURLDataManager>::get(),
+          &ChromeURLDataManager::AddDataSource,
+          html_source));
+  if (!posted) {
+    html_source->AddRef();
+    html_source->Release();  // Keep Valgrind happy in tests.
+  }
+
+  if (!GetProfile()->IsOffTheRecord()) {
     AddMessageHandler((new ShownSectionsHandler())->Attach(this));
     AddMessageHandler((new MostVisitedHandler())->Attach(this));
     AddMessageHandler((new RecentlyClosedTabsHandler())->Attach(this));
@@ -598,18 +507,6 @@ NewTabUI::NewTabUI(TabContents* contents)
 
     AddMessageHandler((new NewTabPageSetHomePageHandler())->Attach(this));
     AddMessageHandler((new PromotionalMessageHandler())->Attach(this));
-
-    NewTabHTMLSource* html_source = new NewTabHTMLSource(GetProfile());
-    bool posted = ChromeThread::PostTask(
-        ChromeThread::IO, FROM_HERE,
-        NewRunnableMethod(
-            Singleton<ChromeURLDataManager>::get(),
-            &ChromeURLDataManager::AddDataSource,
-            html_source));
-    if (!posted) {
-      html_source->AddRef();
-      html_source->Release();  // Keep Valgrind happy in tests.
-    }
   }
 
   // Listen for theme installation.
@@ -757,18 +654,26 @@ void NewTabUI::SetURLTitleAndDirection(DictionaryValue* dictionary,
 ///////////////////////////////////////////////////////////////////////////////
 // NewTabHTMLSource
 
-bool NewTabUI::NewTabHTMLSource::first_view_ = true;
-
 bool NewTabUI::NewTabHTMLSource::first_run_ = true;
 
 NewTabUI::NewTabHTMLSource::NewTabHTMLSource(Profile* profile)
-    : DataSource(chrome::kChromeUINewTabHost, MessageLoop::current()) {
-  InitFullHTML(profile);
+    : DataSource(chrome::kChromeUINewTabHost, MessageLoop::current()),
+      profile_(profile) {
+  static bool first_view = true;
+  if (first_view) {
+    // Decrement ntp promo counters; the default values are specified in
+    // Browser::RegisterUserPrefs.
+    profile->GetPrefs()->SetInteger(prefs::kNTPPromoLineRemaining,
+        profile->GetPrefs()->GetInteger(prefs::kNTPPromoLineRemaining) - 1);
+    profile->GetPrefs()->SetInteger(prefs::kNTPPromoImageRemaining,
+        profile->GetPrefs()->GetInteger(prefs::kNTPPromoImageRemaining) - 1);
+    first_view = false;
+  }
 }
 
 void NewTabUI::NewTabHTMLSource::StartDataRequest(const std::string& path,
     bool is_off_the_record, int request_id) {
-  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
   if (!path.empty()) {
     // A path under new-tab was requested; it's likely a bad relative
     // URL from the new tab page, but in any case it's an error.
@@ -776,219 +681,8 @@ void NewTabUI::NewTabHTMLSource::StartDataRequest(const std::string& path,
     return;
   }
 
-  scoped_refptr<RefCountedBytes> html_bytes(new RefCountedBytes);
-  html_bytes->data.resize(full_html_.size());
-  std::copy(full_html_.begin(), full_html_.end(), html_bytes->data.begin());
+  scoped_refptr<RefCountedBytes> html_bytes =
+      profile_->GetNTPResourceCache()->GetNewTabHTML(is_off_the_record);
 
   SendResponse(request_id, html_bytes);
 }
-
-// static
-std::string NewTabUI::NewTabHTMLSource::GetCustomNewTabPageFromCommandLine() {
-  const CommandLine* command_line = CommandLine::ForCurrentProcess();
-  const std::wstring file_path_wstring = command_line->GetSwitchValue(
-      switches::kNewTabPage);
-
-#if defined(OS_WIN)
-  const FilePath::StringType file_path = file_path_wstring;
-#else
-  const FilePath::StringType file_path = WideToASCII(file_path_wstring);
-#endif
-
-  if (!file_path.empty()) {
-    // Read the file contents in, blocking the UI thread of the browser.
-    // This is for testing purposes only! It is used to test new versions of
-    // the new tab page using a special command line option. Never use this
-    // in a way that will be used by default in product.
-    std::string file_contents;
-    if (file_util::ReadFileToString(FilePath(file_path), &file_contents))
-      return file_contents;
-  }
-
-  return std::string();
-}
-
-void NewTabUI::NewTabHTMLSource::InitFullHTML(Profile* profile) {
-  // Show the profile name in the title and most visited labels if the current
-  // profile is not the default.
-  std::wstring title;
-  std::wstring most_visited;
-  if (UserDataManager::Get()->is_current_profile_default()) {
-    title = l10n_util::GetString(IDS_NEW_TAB_TITLE);
-    most_visited = l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED);
-  } else {
-    // Get the current profile name.
-    std::wstring profile_name =
-      UserDataManager::Get()->current_profile_name();
-    title = l10n_util::GetStringF(IDS_NEW_TAB_TITLE_WITH_PROFILE_NAME,
-                                  profile_name);
-    most_visited = l10n_util::GetStringF(
-        IDS_NEW_TAB_MOST_VISITED_WITH_PROFILE_NAME,
-        profile_name);
-  }
-  DictionaryValue localized_strings;
-  localized_strings.SetString(L"bookmarkbarattached",
-      profile->GetPrefs()->GetBoolean(prefs::kShowBookmarkBar) ?
-      "true" : "false");
-  localized_strings.SetString(L"hasattribution",
-      profile->GetThemeProvider()->HasCustomImage(IDR_THEME_NTP_ATTRIBUTION) ?
-      "true" : "false");
-  localized_strings.SetString(L"title", title);
-  localized_strings.SetString(L"mostvisited", most_visited);
-  localized_strings.SetString(L"searches",
-      l10n_util::GetString(IDS_NEW_TAB_SEARCHES));
-  localized_strings.SetString(L"bookmarks",
-      l10n_util::GetString(IDS_NEW_TAB_BOOKMARKS));
-  localized_strings.SetString(L"recent",
-      l10n_util::GetString(IDS_NEW_TAB_RECENT));
-  localized_strings.SetString(L"showhistory",
-      l10n_util::GetString(IDS_NEW_TAB_HISTORY_SHOW));
-  localized_strings.SetString(L"showhistoryurl",
-      chrome::kChromeUIHistoryURL);
-  localized_strings.SetString(L"editthumbnails",
-      l10n_util::GetString(IDS_NEW_TAB_REMOVE_THUMBNAILS));
-  localized_strings.SetString(L"restorethumbnails",
-      l10n_util::GetString(IDS_NEW_TAB_RESTORE_THUMBNAILS_LINK));
-  localized_strings.SetString(L"editmodeheading",
-      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_EDIT_MODE_HEADING));
-  localized_strings.SetString(L"doneediting",
-      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_DONE_REMOVING_BUTTON));
-  localized_strings.SetString(L"cancelediting",
-      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_CANCEL_REMOVING_BUTTON));
-  localized_strings.SetString(L"searchhistory",
-      l10n_util::GetString(IDS_NEW_TAB_HISTORY_SEARCH));
-  localized_strings.SetString(L"recentlyclosed",
-      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED));
-  localized_strings.SetString(L"mostvisitedintro",
-      l10n_util::GetStringF(IDS_NEW_TAB_MOST_VISITED_INTRO,
-          l10n_util::GetString(IDS_WELCOME_PAGE_URL)));
-  localized_strings.SetString(L"closedwindowsingle",
-      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED_WINDOW_SINGLE));
-  localized_strings.SetString(L"closedwindowmultiple",
-      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED_WINDOW_MULTIPLE));
-  localized_strings.SetString(L"attributionintro",
-      l10n_util::GetString(IDS_NEW_TAB_ATTRIBUTION_INTRO));
-  localized_strings.SetString(L"viewfullhistory",
-      l10n_util::GetString(IDS_NEW_TAB_VIEW_FULL_HISTORY));
-  localized_strings.SetString(L"showthumbnails",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_THUMBNAILS));
-  localized_strings.SetString(L"hidethumbnails",
-      l10n_util::GetString(IDS_NEW_TAB_HIDE_THUMBNAILS));
-  localized_strings.SetString(L"showlist",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_LIST));
-  localized_strings.SetString(L"hidelist",
-      l10n_util::GetString(IDS_NEW_TAB_HIDE_LIST));
-  localized_strings.SetString(L"showrecentlyclosedtabs",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_RECENTLY_CLOSED_TABS));
-  localized_strings.SetString(L"hiderecentlyclosedtabs",
-      l10n_util::GetString(IDS_NEW_TAB_HIDE_RECENTLY_CLOSED_TABS));
-  localized_strings.SetString(L"thumbnailremovednotification",
-      l10n_util::GetString(IDS_NEW_TAB_THUMBNAIL_REMOVED_NOTIFICATION));
-  localized_strings.SetString(L"undothumbnailremove",
-      l10n_util::GetString(IDS_NEW_TAB_UNDO_THUMBNAIL_REMOVE));
-  localized_strings.SetString(L"otrmessage",
-      l10n_util::GetString(IDS_NEW_TAB_OTR_MESSAGE));
-  localized_strings.SetString(L"removethumbnailtooltip",
-      l10n_util::GetString(IDS_NEW_TAB_REMOVE_THUMBNAIL_TOOLTIP));
-  localized_strings.SetString(L"pinthumbnailtooltip",
-      l10n_util::GetString(IDS_NEW_TAB_PIN_THUMBNAIL_TOOLTIP));
-  localized_strings.SetString(L"unpinthumbnailtooltip",
-      l10n_util::GetString(IDS_NEW_TAB_UNPIN_THUMBNAIL_TOOLTIP));
-  localized_strings.SetString(L"showhidethumbnailtooltip",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_THUMBNAIL_TOOLTIP));
-  localized_strings.SetString(L"showhidelisttooltip",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_LIST_TOOLTIP));
-  localized_strings.SetString(L"pagedisplaytooltip",
-      l10n_util::GetString(IDS_NEW_TAB_PAGE_DISPLAY_TOOLTIP));
-  localized_strings.SetString(L"firstrunnotification",
-      l10n_util::GetString(IDS_NEW_TAB_FIRST_RUN_NOTIFICATION));
-  localized_strings.SetString(L"closefirstrunnotification",
-      l10n_util::GetString(IDS_NEW_TAB_CLOSE_FIRST_RUN_NOTIFICATION));
-  localized_strings.SetString(L"makethishomepage",
-      l10n_util::GetString(IDS_NEW_TAB_MAKE_THIS_HOMEPAGE));
-  localized_strings.SetString(L"themelink",
-      l10n_util::GetString(IDS_THEMES_GALLERY_URL));
-  localized_strings.SetString(L"tips",
-      l10n_util::GetString(IDS_NEW_TAB_TIPS));
-  localized_strings.SetString(L"sync",
-      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_BOOKMARK_SYNC));
-  localized_strings.SetString(L"promonew",
-      l10n_util::GetString(IDS_NTP_PROMOTION_NEW));
-  localized_strings.SetString(L"promomessage",
-      l10n_util::GetStringF(IDS_NTP_PROMOTION_MESSAGE,
-          l10n_util::GetString(IDS_PRODUCT_NAME),
-          ASCIIToWide(Extension::kGalleryBrowseUrl),
-          l10n_util::GetString(IDS_SYNC_SERVICE_HELP_URL)));
-  localized_strings.SetString(L"extensionslink",
-      ASCIIToWide(Extension::kGalleryBrowseUrl));
-
-  // Don't initiate the sync related message passing with the page if the sync
-  // code is not present.
-  if (profile->GetProfileSyncService())
-    localized_strings.SetString(L"syncispresent", "true");
-  else
-    localized_strings.SetString(L"syncispresent", "false");
-
-  if (!profile->GetPrefs()->GetBoolean(prefs::kHomePageIsNewTabPage))
-    localized_strings.SetString(L"showsetashomepage", "true");
-
-  SetFontAndTextDirection(&localized_strings);
-
-  // Let the tab know whether it's the first tab being viewed.
-  if (first_view_) {
-    // Decrement ntp promo counters; the default values are specified in
-    // Browser::RegisterUserPrefs.
-    profile->GetPrefs()->SetInteger(prefs::kNTPPromoLineRemaining,
-        profile->GetPrefs()->GetInteger(prefs::kNTPPromoLineRemaining) - 1);
-    profile->GetPrefs()->SetInteger(prefs::kNTPPromoImageRemaining,
-        profile->GetPrefs()->GetInteger(prefs::kNTPPromoImageRemaining) - 1);
-    first_view_ = false;
-  }
-
-  // Control fade and resize animations.
-  std::wstring anim =
-      Animation::ShouldRenderRichAnimation() ? L"true" : L"false";
-  localized_strings.SetString(L"anim", anim);
-
-  // Pass the shown_sections pref early so that we can prevent flicker.
-  const int shown_sections = profile->GetPrefs()->GetInteger(
-      prefs::kNTPShownSections);
-  localized_strings.SetInteger(L"shown_sections", shown_sections);
-
-  // In case we have the new new tab page enabled we first try to read the file
-  // provided on the command line. If that fails we just get the resource from
-  // the resource bundle.
-  base::StringPiece new_tab_html;
-  std::string new_tab_html_str;
-  new_tab_html_str = GetCustomNewTabPageFromCommandLine();
-
-  if (!new_tab_html_str.empty()) {
-    new_tab_html = base::StringPiece(new_tab_html_str);
-  }
-
-  if (new_tab_html.empty()) {
-    new_tab_html = ResourceBundle::GetSharedInstance().GetRawDataResource(
-        IDR_NEW_NEW_TAB_HTML);
-  }
-
-  // Inject the template data into the HTML so that it is available before any
-  // layout is needed.
-  std::string json_html;
-  jstemplate_builder::AppendJsonHtml(&localized_strings, &json_html);
-
-  static const base::StringPiece template_data_placeholder(
-      "<!-- template data placeholder -->");
-  size_t pos = new_tab_html.find(template_data_placeholder);
-
-  if (pos != base::StringPiece::npos) {
-    full_html_.assign(new_tab_html.data(), pos);
-    full_html_.append(json_html);
-    size_t after_offset = pos + template_data_placeholder.size();
-    full_html_.append(new_tab_html.data() + after_offset,
-                      new_tab_html.size() - after_offset);
-  } else {
-    NOTREACHED();
-    full_html_.assign(new_tab_html.data(), new_tab_html.size());
-  }
-  jstemplate_builder::AppendI18nTemplateProcessHtml(&full_html_);
-}
diff --git a/chrome/browser/dom_ui/new_tab_ui.h b/chrome/browser/dom_ui/new_tab_ui.h
index b00aca8..d612dd9 100644
--- a/chrome/browser/dom_ui/new_tab_ui.h
+++ b/chrome/browser/dom_ui/new_tab_ui.h
@@ -63,18 +63,6 @@ class NewTabUI : public DOMUI,
       return "text/html";
     }
 
-    virtual MessageLoop* MessageLoopForRequestPath(const std::string& path)
-        const {
-      // NewTabHTMLSource does all of the operations that need to be on the
-      // UI thread from InitFullHTML, called by the constructor.  It is safe
-      // to call StartDataRequest from any thread, so return NULL.
-      return NULL;
-    }
-
-    // Setters and getters for first_view.
-    static void set_first_view(bool first_view) { first_view_ = first_view; }
-    static bool first_view() { return first_view_; }
-
     // Setters and getters for first_run.
     static void set_first_run(bool first_run) { first_run_ = first_run; }
     static bool first_run() { return first_run_; }
@@ -82,29 +70,12 @@ class NewTabUI : public DOMUI,
    private:
     ~NewTabHTMLSource() {}
 
-    // In case a file path to the new tab page was provided this tries to load
-    // the file and returns the file content if successful. This returns an
-    // empty string in case of failure.
-    static std::string GetCustomNewTabPageFromCommandLine();
-
-    // Populate full_html_.  This must be called from the UI thread because it
-    // involves profile access.
-    //
-    // A new NewTabHTMLSource object is used for each new tab page instance
-    // and each reload of an existing new tab page, so there is no concern
-    // about cached data becoming stale.
-    void InitFullHTML(Profile* profile);
-
-    // The content to be served by StartDataRequest, stored by InitFullHTML.
-    std::string full_html_;
-
-    // Whether this is the first viewing of the new tab page and
-    // we think it is the user's startup page.
-    static bool first_view_;
-
     // Whether this is the first run.
     static bool first_run_;
 
+    // Pointer back to the original profile.
+    Profile* profile_;
+
     DISALLOW_COPY_AND_ASSIGN(NewTabHTMLSource);
   };
 
@@ -124,14 +95,6 @@ class NewTabUI : public DOMUI,
 
   NotificationRegistrar registrar_;
 
-  // The message id that should be displayed in this NewTabUIContents
-  // instance's motd area.
-  int motd_message_id_;
-
-  // Whether the user is in incognito mode or not, used to determine
-  // what HTML to load.
-  bool incognito_;
-
   // The preference version. This used for migrating prefs of the NTP.
   static const int current_pref_version_ = 1;
 
diff --git a/chrome/browser/dom_ui/ntp_resource_cache.cc b/chrome/browser/dom_ui/ntp_resource_cache.cc
new file mode 100644
index 0000000..e8c7402
--- /dev/null
+++ b/chrome/browser/dom_ui/ntp_resource_cache.cc
@@ -0,0 +1,298 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/dom_ui/ntp_resource_cache.h"
+
+#include "app/animation.h"
+#include "app/l10n_util.h"
+#include "app/resource_bundle.h"
+#include "app/theme_provider.h"
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/ref_counted_memory.h"
+#include "base/values.h"
+#include "chrome/browser/dom_ui/chrome_url_data_manager.h"
+#include "chrome/browser/profile.h"
+#include "chrome/browser/user_data_manager.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/jstemplate_builder.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/notification_type.h"
+#include "chrome/common/pref_names.h"
+#include "chrome/common/pref_service.h"
+#include "chrome/common/url_constants.h"
+#include "grit/browser_resources.h"
+#include "grit/chromium_strings.h"
+#include "grit/generated_resources.h"
+#include "grit/locale_settings.h"
+#include "grit/theme_resources.h"
+
+namespace {
+
+// In case a file path to the new tab page was provided this tries to load
+// the file and returns the file content if successful. This returns an
+// empty string in case of failure.
+std::string GetCustomNewTabPageFromCommandLine() {
+  const CommandLine* command_line = CommandLine::ForCurrentProcess();
+  const FilePath file_path = command_line->GetSwitchValuePath(
+      switches::kNewTabPage);
+
+  if (!file_path.empty()) {
+    // Read the file contents in, blocking the UI thread of the browser.
+    // This is for testing purposes only! It is used to test new versions of
+    // the new tab page using a special command line option. Never use this
+    // in a way that will be used by default in product.
+    std::string file_contents;
+    if (file_util::ReadFileToString(FilePath(file_path), &file_contents))
+      return file_contents;
+  }
+
+  return std::string();
+}
+
+}
+
+NTPResourceCache::NTPResourceCache(Profile* profile) : profile_(profile) {
+  registrar_.Add(this, NotificationType::BROWSER_THEME_CHANGED,
+                 NotificationService::AllSources());
+
+  // Watch for pref changes that cause us to need to invalidate the cache.
+  PrefService* pref_service = profile_->GetPrefs();
+  pref_service->AddPrefObserver(prefs::kShowBookmarkBar, this);
+  pref_service->AddPrefObserver(prefs::kHomePageIsNewTabPage, this);
+  pref_service->AddPrefObserver(prefs::kNTPShownSections, this);
+}
+
+NTPResourceCache::~NTPResourceCache() {
+  PrefService* pref_service = profile_->GetPrefs();
+  pref_service->RemovePrefObserver(prefs::kShowBookmarkBar, this);
+  pref_service->RemovePrefObserver(prefs::kHomePageIsNewTabPage, this);
+  pref_service->RemovePrefObserver(prefs::kNTPShownSections, this);
+}
+
+RefCountedBytes* NTPResourceCache::GetNewTabHTML(bool is_off_the_record) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+  if (is_off_the_record) {
+    if (!new_tab_incognito_html_.get())
+      CreateNewTabIncognitoHtml();
+  } else {
+    if (!new_tab_html_.get())
+      CreateNewTabHtml();
+  }
+  return is_off_the_record ? new_tab_incognito_html_.get()
+                           : new_tab_html_.get();
+}
+
+void NTPResourceCache::Observe(NotificationType type,
+    const NotificationSource& source, const NotificationDetails& details) {
+  new_tab_incognito_html_ = NULL;
+  new_tab_html_ = NULL;
+}
+
+void NTPResourceCache::CreateNewTabIncognitoHtml() {
+  DictionaryValue localized_strings;
+  localized_strings.SetString(L"title",
+      l10n_util::GetString(IDS_NEW_TAB_TITLE));
+  localized_strings.SetString(L"content",
+      l10n_util::GetStringF(IDS_NEW_TAB_OTR_MESSAGE,
+          l10n_util::GetString(IDS_LEARN_MORE_INCOGNITO_URL)));
+  bool bookmark_bar_attached = profile_->GetPrefs()->GetBoolean(
+      prefs::kShowBookmarkBar);
+  localized_strings.SetString(L"bookmarkbarattached",
+      bookmark_bar_attached ? "true" : "false");
+
+  ChromeURLDataManager::DataSource::SetFontAndTextDirection(&localized_strings);
+
+  static const base::StringPiece incognito_tab_html(
+      ResourceBundle::GetSharedInstance().GetRawDataResource(
+          IDR_INCOGNITO_TAB_HTML));
+
+  std::string full_html = jstemplate_builder::GetI18nTemplateHtml(
+      incognito_tab_html, &localized_strings);
+
+  new_tab_incognito_html_ = new RefCountedBytes;
+  new_tab_incognito_html_->data.resize(full_html.size());
+  std::copy(full_html.begin(), full_html.end(),
+            new_tab_incognito_html_->data.begin());
+}
+
+void NTPResourceCache::CreateNewTabHtml() {
+  // Show the profile name in the title and most visited labels if the current
+  // profile is not the default.
+  std::wstring title;
+  std::wstring most_visited;
+  if (UserDataManager::Get()->is_current_profile_default()) {
+    title = l10n_util::GetString(IDS_NEW_TAB_TITLE);
+    most_visited = l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED);
+  } else {
+    // Get the current profile name.
+    std::wstring profile_name =
+      UserDataManager::Get()->current_profile_name();
+    title = l10n_util::GetStringF(IDS_NEW_TAB_TITLE_WITH_PROFILE_NAME,
+                                  profile_name);
+    most_visited = l10n_util::GetStringF(
+        IDS_NEW_TAB_MOST_VISITED_WITH_PROFILE_NAME,
+        profile_name);
+  }
+  DictionaryValue localized_strings;
+  localized_strings.SetString(L"bookmarkbarattached",
+      profile_->GetPrefs()->GetBoolean(prefs::kShowBookmarkBar) ?
+      "true" : "false");
+  localized_strings.SetString(L"hasattribution",
+      profile_->GetThemeProvider()->HasCustomImage(IDR_THEME_NTP_ATTRIBUTION) ?
+      "true" : "false");
+  localized_strings.SetString(L"title", title);
+  localized_strings.SetString(L"mostvisited", most_visited);
+  localized_strings.SetString(L"searches",
+      l10n_util::GetString(IDS_NEW_TAB_SEARCHES));
+  localized_strings.SetString(L"bookmarks",
+      l10n_util::GetString(IDS_NEW_TAB_BOOKMARKS));
+  localized_strings.SetString(L"recent",
+      l10n_util::GetString(IDS_NEW_TAB_RECENT));
+  localized_strings.SetString(L"showhistory",
+      l10n_util::GetString(IDS_NEW_TAB_HISTORY_SHOW));
+  localized_strings.SetString(L"showhistoryurl",
+      chrome::kChromeUIHistoryURL);
+  localized_strings.SetString(L"editthumbnails",
+      l10n_util::GetString(IDS_NEW_TAB_REMOVE_THUMBNAILS));
+  localized_strings.SetString(L"restorethumbnails",
+      l10n_util::GetString(IDS_NEW_TAB_RESTORE_THUMBNAILS_LINK));
+  localized_strings.SetString(L"editmodeheading",
+      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_EDIT_MODE_HEADING));
+  localized_strings.SetString(L"doneediting",
+      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_DONE_REMOVING_BUTTON));
+  localized_strings.SetString(L"cancelediting",
+      l10n_util::GetString(IDS_NEW_TAB_MOST_VISITED_CANCEL_REMOVING_BUTTON));
+  localized_strings.SetString(L"searchhistory",
+      l10n_util::GetString(IDS_NEW_TAB_HISTORY_SEARCH));
+  localized_strings.SetString(L"recentlyclosed",
+      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED));
+  localized_strings.SetString(L"mostvisitedintro",
+      l10n_util::GetStringF(IDS_NEW_TAB_MOST_VISITED_INTRO,
+          l10n_util::GetString(IDS_WELCOME_PAGE_URL)));
+  localized_strings.SetString(L"closedwindowsingle",
+      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED_WINDOW_SINGLE));
+  localized_strings.SetString(L"closedwindowmultiple",
+      l10n_util::GetString(IDS_NEW_TAB_RECENTLY_CLOSED_WINDOW_MULTIPLE));
+  localized_strings.SetString(L"attributionintro",
+      l10n_util::GetString(IDS_NEW_TAB_ATTRIBUTION_INTRO));
+  localized_strings.SetString(L"viewfullhistory",
+      l10n_util::GetString(IDS_NEW_TAB_VIEW_FULL_HISTORY));
+  localized_strings.SetString(L"showthumbnails",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_THUMBNAILS));
+  localized_strings.SetString(L"hidethumbnails",
+      l10n_util::GetString(IDS_NEW_TAB_HIDE_THUMBNAILS));
+  localized_strings.SetString(L"showlist",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_LIST));
+  localized_strings.SetString(L"hidelist",
+      l10n_util::GetString(IDS_NEW_TAB_HIDE_LIST));
+  localized_strings.SetString(L"showrecentlyclosedtabs",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_RECENTLY_CLOSED_TABS));
+  localized_strings.SetString(L"hiderecentlyclosedtabs",
+      l10n_util::GetString(IDS_NEW_TAB_HIDE_RECENTLY_CLOSED_TABS));
+  localized_strings.SetString(L"thumbnailremovednotification",
+      l10n_util::GetString(IDS_NEW_TAB_THUMBNAIL_REMOVED_NOTIFICATION));
+  localized_strings.SetString(L"undothumbnailremove",
+      l10n_util::GetString(IDS_NEW_TAB_UNDO_THUMBNAIL_REMOVE));
+  localized_strings.SetString(L"otrmessage",
+      l10n_util::GetString(IDS_NEW_TAB_OTR_MESSAGE));
+  localized_strings.SetString(L"removethumbnailtooltip",
+      l10n_util::GetString(IDS_NEW_TAB_REMOVE_THUMBNAIL_TOOLTIP));
+  localized_strings.SetString(L"pinthumbnailtooltip",
+      l10n_util::GetString(IDS_NEW_TAB_PIN_THUMBNAIL_TOOLTIP));
+  localized_strings.SetString(L"unpinthumbnailtooltip",
+      l10n_util::GetString(IDS_NEW_TAB_UNPIN_THUMBNAIL_TOOLTIP));
+  localized_strings.SetString(L"showhidethumbnailtooltip",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_THUMBNAIL_TOOLTIP));
+  localized_strings.SetString(L"showhidelisttooltip",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_LIST_TOOLTIP));
+  localized_strings.SetString(L"pagedisplaytooltip",
+      l10n_util::GetString(IDS_NEW_TAB_PAGE_DISPLAY_TOOLTIP));
+  localized_strings.SetString(L"firstrunnotification",
+      l10n_util::GetString(IDS_NEW_TAB_FIRST_RUN_NOTIFICATION));
+  localized_strings.SetString(L"closefirstrunnotification",
+      l10n_util::GetString(IDS_NEW_TAB_CLOSE_FIRST_RUN_NOTIFICATION));
+  localized_strings.SetString(L"makethishomepage",
+      l10n_util::GetString(IDS_NEW_TAB_MAKE_THIS_HOMEPAGE));
+  localized_strings.SetString(L"themelink",
+      l10n_util::GetString(IDS_THEMES_GALLERY_URL));
+  localized_strings.SetString(L"tips",
+      l10n_util::GetString(IDS_NEW_TAB_TIPS));
+  localized_strings.SetString(L"sync",
+      l10n_util::GetString(IDS_NEW_TAB_SHOW_HIDE_BOOKMARK_SYNC));
+  localized_strings.SetString(L"promonew",
+      l10n_util::GetString(IDS_NTP_PROMOTION_NEW));
+  localized_strings.SetString(L"promomessage",
+      l10n_util::GetStringF(IDS_NTP_PROMOTION_MESSAGE,
+          l10n_util::GetString(IDS_PRODUCT_NAME),
+          ASCIIToWide(Extension::kGalleryBrowseUrl),
+          l10n_util::GetString(IDS_SYNC_SERVICE_HELP_URL)));
+  localized_strings.SetString(L"extensionslink",
+      ASCIIToWide(Extension::kGalleryBrowseUrl));
+
+  // Don't initiate the sync related message passing with the page if the sync
+  // code is not present.
+  if (profile_->GetProfileSyncService())
+    localized_strings.SetString(L"syncispresent", "true");
+  else
+    localized_strings.SetString(L"syncispresent", "false");
+
+  if (!profile_->GetPrefs()->GetBoolean(prefs::kHomePageIsNewTabPage))
+    localized_strings.SetString(L"showsetashomepage", "true");
+
+  ChromeURLDataManager::DataSource::SetFontAndTextDirection(&localized_strings);
+
+  // Control fade and resize animations.
+  std::string anim =
+      Animation::ShouldRenderRichAnimation() ? "true" : "false";
+  localized_strings.SetString(L"anim", anim);
+
+  // Pass the shown_sections pref early so that we can prevent flicker.
+  const int shown_sections = profile_->GetPrefs()->GetInteger(
+      prefs::kNTPShownSections);
+  localized_strings.SetInteger(L"shown_sections", shown_sections);
+
+  // In case we have the new new tab page enabled we first try to read the file
+  // provided on the command line. If that fails we just get the resource from
+  // the resource bundle.
+  base::StringPiece new_tab_html;
+  std::string new_tab_html_str;
+  new_tab_html_str = GetCustomNewTabPageFromCommandLine();
+
+  if (!new_tab_html_str.empty()) {
+    new_tab_html = base::StringPiece(new_tab_html_str);
+  }
+
+  if (new_tab_html.empty()) {
+    new_tab_html = ResourceBundle::GetSharedInstance().GetRawDataResource(
+        IDR_NEW_NEW_TAB_HTML);
+  }
+
+  // Inject the template data into the HTML so that it is available before any
+  // layout is needed.
+  std::string json_html;
+  jstemplate_builder::AppendJsonHtml(&localized_strings, &json_html);
+
+  static const base::StringPiece template_data_placeholder(
+      "<!-- template data placeholder -->");
+  size_t pos = new_tab_html.find(template_data_placeholder);
+
+  std::string full_html;
+  if (pos != base::StringPiece::npos) {
+    full_html.assign(new_tab_html.data(), pos);
+    full_html.append(json_html);
+    size_t after_offset = pos + template_data_placeholder.size();
+    full_html.append(new_tab_html.data() + after_offset,
+                     new_tab_html.size() - after_offset);
+  } else {
+    NOTREACHED();
+    full_html.assign(new_tab_html.data(), new_tab_html.size());
+  }
+  jstemplate_builder::AppendI18nTemplateProcessHtml(&full_html);
+
+  new_tab_html_ = new RefCountedBytes;
+  new_tab_html_->data.resize(full_html.size());
+  std::copy(full_html.begin(), full_html.end(), new_tab_html_->data.begin());
+}
diff --git a/chrome/browser/dom_ui/ntp_resource_cache.h b/chrome/browser/dom_ui/ntp_resource_cache.h
new file mode 100644
index 0000000..a39b962
--- /dev/null
+++ b/chrome/browser/dom_ui/ntp_resource_cache.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_DOM_UI_NTP_RESOURCE_CACHE_H_
+#define CHROME_BROWSER_DOM_UI_NTP_RESOURCE_CACHE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/ref_counted.h"
+#include "chrome/common/notification_registrar.h"
+
+class Profile;
+class RefCountedBytes;
+
+// This class keeps a cache of NTP resources (HTML and CSS) so we don't have to
+// regenerate them all the time.
+class NTPResourceCache : public NotificationObserver {
+ public:
+  explicit NTPResourceCache(Profile* profile);
+  virtual ~NTPResourceCache();
+
+  RefCountedBytes* GetNewTabHTML(bool is_off_the_record);
+
+  // NotificationObserver interface.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+ private:
+  Profile* profile_;
+
+  void CreateNewTabIncognitoHtml();
+  scoped_refptr<RefCountedBytes> new_tab_incognito_html_;
+
+  void CreateNewTabHtml();
+  scoped_refptr<RefCountedBytes> new_tab_html_;
+
+  NotificationRegistrar registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(NTPResourceCache);
+};
+
+#endif  // CHROME_BROWSER_DOM_UI_NTP_RESOURCE_CACHE_H_
diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index c1cd54d..eb998ba 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/browser_list.h"
 #include "chrome/browser/browser_theme_provider.h"
 #include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/dom_ui/ntp_resource_cache.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/extensions/extension_devtools_manager.h"
 #include "chrome/browser/extensions/extension_message_service.h"
@@ -515,6 +516,11 @@ class OffTheRecordProfileImpl : public Profile,
     NOTREACHED();
   }
 
+  virtual NTPResourceCache* GetNTPResourceCache() {
+    // Just return the real profile resource cache.
+    return profile_->GetNTPResourceCache();
+  }
+
   virtual void ExitedOffTheRecordMode() {
     // Drop our download manager so we forget about all the downloads made
     // in off-the-record mode.
@@ -721,6 +727,12 @@ void ProfileImpl::InitWebResources() {
   web_resource_service_->StartAfterDelay();
 }
 
+NTPResourceCache* ProfileImpl::GetNTPResourceCache() {
+  if (!ntp_resource_cache_.get())
+    ntp_resource_cache_.reset(new NTPResourceCache(this));
+  return ntp_resource_cache_.get();
+}
+
 ProfileImpl::~ProfileImpl() {
   tab_restore_service_ = NULL;
 
@@ -749,6 +761,9 @@ ProfileImpl::~ProfileImpl() {
   prefs->RemovePrefObserver(prefs::kEnableSpellCheck, this);
   prefs->RemovePrefObserver(prefs::kEnableAutoSpellCorrect, this);
 
+  // Delete the NTP resource cache so we can unregister pref observers.
+  ntp_resource_cache_.reset();
+
   sync_service_.reset();
 
   // Both HistoryService and WebDataService maintain threads for background
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index 98e7aab..b8cec92 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -47,6 +47,7 @@ class ExtensionsService;
 class FaviconService;
 class HistoryService;
 class NavigationController;
+class NTPResourceCache;
 class PasswordStore;
 class PersonalDataManager;
 class PrefService;
@@ -382,6 +383,9 @@ class Profile {
   // Start up service that gathers data from web resource feeds.
   virtual void InitWebResources() = 0;
 
+  // Returns the new tab page resource cache.
+  virtual NTPResourceCache* GetNTPResourceCache() = 0;
+
 #ifdef UNIT_TEST
   // Use with caution.  GetDefaultRequestContext may be called on any thread!
   static void set_default_request_context(URLRequestContextGetter* c) {
@@ -481,6 +485,7 @@ class ProfileImpl : public Profile,
   virtual void MarkAsCleanShutdown();
   virtual void InitExtensions();
   virtual void InitWebResources();
+  virtual NTPResourceCache* GetNTPResourceCache();
   virtual ProfileSyncService* GetProfileSyncService();
   void InitSyncService();
 
@@ -539,6 +544,7 @@ class ProfileImpl : public Profile,
   scoped_ptr<TemplateURLModel> template_url_model_;
   scoped_ptr<BookmarkModel> bookmark_bar_model_;
   scoped_refptr<WebResourceService> web_resource_service_;
+  scoped_ptr<NTPResourceCache> ntp_resource_cache_;
 
   scoped_ptr<ProfileSyncService> sync_service_;
 
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 970a4e0..f10d7f6 100755
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -562,6 +562,8 @@
         'browser/dom_ui/new_tab_page_sync_handler.h',
         'browser/dom_ui/new_tab_ui.cc',
         'browser/dom_ui/new_tab_ui.h',
+        'browser/dom_ui/ntp_resource_cache.cc',
+        'browser/dom_ui/ntp_resource_cache.h',
         'browser/dom_ui/print_ui.cc',
         'browser/dom_ui/print_ui.h',
         'browser/dom_ui/shown_sections_handler.cc',
diff --git a/chrome/test/testing_profile.h b/chrome/test/testing_profile.h
index 14b64da..40b6896 100644
--- a/chrome/test/testing_profile.h
+++ b/chrome/test/testing_profile.h
@@ -187,6 +187,7 @@ class TestingProfile : public Profile {
   virtual void MarkAsCleanShutdown() {}
   virtual void InitExtensions() {}
   virtual void InitWebResources() {}
+  virtual NTPResourceCache* GetNTPResourceCache() { return NULL; }
   virtual DesktopNotificationService* GetDesktopNotificationService() {
     return NULL;
   }