Fall back to local page if online NTP fails to load.

chrome/browser/ui/search/instant_controller.h

 // Copyright 2012 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_UI_SEARCH_INSTANT_CONTROLLER_H_
 #define CHROME_BROWSER_UI_SEARCH_INSTANT_CONTROLLER_H_
 
 #include <list>
 #include <map>
 #include <string>
@@ skipping 263 matching lines @@
 
   // Invoked by the InstantLoader when the Instant page wants to undo a
   // Most Visited deletion.
   virtual void UndoMostVisitedDeletion(InstantRestrictedID most_visited_item_id)
       OVERRIDE;
 
   // Invoked by the InstantLoader when the Instant page wants to undo all
   // Most Visited deletions.
   virtual void UndoAllMostVisitedDeletions() OVERRIDE;
 
+  // Invoked by the InstantLoader when the Instant page is preloaded as the
+  // NTP and is ready to display.
+  virtual void InstantPageLoadFailed(content::WebContents* contents) OVERRIDE;

[samarth, 2013/04/30 17:10:33]

Put this with the rest of the InstantPage::Delegate overrides (and no need to
repeat the comment).

[David Black, 2013/04/30 23:09:08]

Done.

+
+  // Helper function to navigate the given contents to the local fallback
+  // Instant URL and trim the history correctly.
+  void RedirectToLocalNTP(content::WebContents* contents);
+
   // Helper for OmniboxFocusChanged. Commit or discard the overlay.
   void OmniboxLostFocus(gfx::NativeView view_gaining_focus);
 
   // Creates a new NTP, using the instant_url property of the default
   // TemplateURL, or chrome::kChromeSearchLocalNTPURL if |use_local_ntp| is
   // true. For |ignore_blacklist| look at comments in GetInstantURL().
   void ResetNTP(bool ignore_blacklist, bool use_local_ntp);
 
   // Ensures that |overlay_| uses the Instant URL returned by GetInstantURL(),
   // creating a new overlay if necessary. In extended mode, will fallback to
@@ skipping 180 matching lines @@
   // Used for Top Sites async retrieval.
   base::WeakPtrFactory<InstantController> weak_ptr_factory_;
 
   // Used to get notifications about Most Visted changes.
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(InstantController);
 };
 
 #endif  // CHROME_BROWSER_UI_SEARCH_INSTANT_CONTROLLER_H_