[New Tab Page] Change the mechanism to intercept online NTP errors

chrome/browser/ui/search/search_tab_helper.h

Index: chrome/browser/ui/search/search_tab_helper.h
diff --git a/chrome/browser/ui/search/search_tab_helper.h b/chrome/browser/ui/search/search_tab_helper.h
index 764afa188ee648fbc3e46c41b4309c08be7564b5..f5548ba1b02f44c4cbeebc1f305e52c4887af695 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -153,10 +153,6 @@ class SearchTabHelper : public content::WebContentsObserver,
   void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) override;
-  void DidFailProvisionalLoad(content::RenderFrameHost* render_frame_host,
-                              const GURL& validated_url,
-                              int error_code,
-                              const base::string16& error_description) override;
   void DidFinishLoad(content::RenderFrameHost* render_frame_host,
                      const GURL& validated_url) override;
   void NavigationEntryCommitted(
@@ -204,10 +200,6 @@ class SearchTabHelper : public content::WebContentsObserver,
 
   Profile* profile() const;
 
-  // Helper function to navigate the given contents to the local fallback
-  // Instant URL and trim the history correctly.
-  void RedirectToLocalNTP();
-
   // Returns whether input is in progress, i.e. if the omnibox has focus and the
   // active tab is in mode SEARCH_SUGGESTIONS.
   bool IsInputInProgress() const;