Add an error page for resources blocked via XSS Auditor.

third_party/WebKit/public/web/WebFrameClient.h

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 253 matching lines @@
                                       const WebString& stackTrace) {}
 
   // Load commands -------------------------------------------------------
 
   // The client should handle the navigation externally.
   virtual void loadURLExternally(const WebURLRequest&,
                                  WebNavigationPolicy,
                                  const WebString& downloadName,
                                  bool shouldReplaceCurrentEntry) {}
 
+  // The client should load an error page in the current frame.
+  virtual void loadErrorPage(int reason) {}
+
   // Navigational queries ------------------------------------------------
 
   // The client may choose to alter the navigation policy.  Otherwise,
   // defaultPolicy should just be returned.
 
   struct NavigationPolicyInfo {
     WebDataSource::ExtraData* extraData;
 
     // Note: if browser side navigations are enabled, the client may modify
     // the urlRequest. However, should this happen, the client should change
@@ skipping 471 matching lines @@
   // Overwrites the given URL to use an HTML5 embed if possible.
   // An empty URL is returned if the URL is not overriden.
   virtual WebURL overrideFlashEmbedWithHTML(const WebURL& url) {
     return WebURL();
   }
 };
 
 }  // namespace blink
 
 #endif