Add the main frame routing ID to WebContentsDelegate, use it in BackgroundContents.

content/shell/browser/shell.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_SHELL_BROWSER_SHELL_H_
 #define CONTENT_SHELL_BROWSER_SHELL_H_
 
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 66 matching lines @@
   // Resizes the web content view to the given dimensions.
   void SizeTo(const gfx::Size& content_size);
 #endif
 
   // Do one time initialization at application startup.
   static void Initialize();
 
   static Shell* CreateNewWindow(BrowserContext* browser_context,
                                 const GURL& url,
                                 SiteInstance* site_instance,
-                                int routing_id,
                                 const gfx::Size& initial_size);
 
   // Returns the Shell object corresponding to the given RenderViewHost.
   static Shell* FromRenderViewHost(RenderViewHost* rvh);
 
   // Returns the currently open windows.
   static std::vector<Shell*>& windows() { return windows_; }
 
   // Closes all windows and returns. This runs a message loop.
   static void CloseAllWindows();
@@ skipping 158 matching lines @@
   static base::Callback<void(Shell*)> shell_created_callback_;
 
   // True if the destructur of Shell should post a quit closure on the current
   // message loop if the destructed Shell object was the last one.
   static bool quit_message_loop_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_H_