Add helper method to check for invalid message source.

content/browser/web_contents/web_contents_impl.h

 // Copyright (c) 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 CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 734 matching lines @@
                       int render_frame_id,
                       IPC::Message* reply_msg,
                       bool dialog_was_suppressed,
                       bool success,
                       const base::string16& user_input);
 
   bool OnMessageReceived(RenderViewHost* render_view_host,
                          RenderFrameHost* render_frame_host,
                          const IPC::Message& message);
 
+  // Checks whether render_frame_message_source_ is set to non-null value,
+  // otherwise it terminates the main frame renderer process.
+  bool HasValidFrameSource();
+
   // IPC message handlers.
   void OnThemeColorChanged(SkColor theme_color);
   void OnDidLoadResourceFromMemoryCache(const GURL& url,
                                         const std::string& security_info,
                                         const std::string& http_request,
                                         const std::string& mime_type,
                                         ResourceType resource_type);
   void OnDidDisplayInsecureContent();
   void OnDidRunInsecureContent(const std::string& security_origin,
                                const GURL& target_url);
@@ skipping 504 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_