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

chrome/browser/ui/search/instant_tab.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_TAB_H_
 #define CHROME_BROWSER_UI_SEARCH_INSTANT_TAB_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/ui/search/instant_page.h"
 
 // InstantTab represents a committed page (i.e. an actual tab on the tab strip)
 // that supports the Instant API.
 class InstantTab : public InstantPage {
  public:
   explicit InstantTab(InstantPage::Delegate* delegate);
   virtual ~InstantTab();
 
   // Start observing |contents| for messages. Sends a message to determine if
   // the page supports the Instant API.
   void Init(content::WebContents* contents);
 
  private:
   // Overridden from InstantPage:
+  virtual bool ShouldProcessAboutToNavigateMainFrame() OVERRIDE;
   virtual bool ShouldProcessSetSuggestions() OVERRIDE;
   virtual bool ShouldProcessFocusOmnibox() OVERRIDE;
   virtual bool ShouldProcessNavigateToURL() OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(InstantTab);
 };
 
 #endif  // CHROME_BROWSER_UI_SEARCH_INSTANT_TAB_H_