Use a resource throttle to implement shouldOverrideUrlLoading.

content/browser/frame_host/navigator_delegate.h

 // Copyright 2013 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 CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_
 
 #include "base/strings/string16.h"
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/navigation_controller.h"
@@ skipping 26 matching lines @@
   // A provisional load in |render_frame_host| failed.
   virtual void DidFailProvisionalLoadWithError(
       RenderFrameHostImpl* render_frame_host,
       const FrameHostMsg_DidFailProvisionalLoadWithError_Params& params) {}
 
   // Document load in |render_frame_host| failed.
   virtual void DidFailLoadWithError(
       RenderFrameHostImpl* render_frame_host,
       const GURL& url,
       int error_code,
-      const base::string16& error_description) {}
+      const base::string16& error_description,
+      bool was_ignored_by_handler) {}
 
   // A navigation was committed in |render_frame_host|.
   virtual void DidCommitProvisionalLoad(
       RenderFrameHostImpl* render_frame_host,
       const GURL& url,
       ui::PageTransition transition_type) {}
 
   // Handles post-navigation tasks in navigation BEFORE the entry has been
   // committed to the NavigationController.
   virtual void DidNavigateMainFramePreCommit(bool navigation_is_within_page) {}
@@ skipping 50 matching lines @@
   // throbber stopping.
   virtual void DidStopLoading() {}
 
   // The load progress was changed.
   virtual void DidChangeLoadProgress() {}
 };
 
 }  // namspace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_