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

chrome/browser/tab_contents/background_contents.h

 // Copyright (c) 2011 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 CHROME_BROWSER_TAB_CONTENTS_BACKGROUND_CONTENTS_H_
 #define CHROME_BROWSER_TAB_CONTENTS_BACKGROUND_CONTENTS_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 28 matching lines @@
                                 bool user_gesture,
                                 bool* was_blocked) = 0;
 
    protected:
     virtual ~Delegate() {}
   };
 
   BackgroundContents(
       content::SiteInstance* site_instance,
       int routing_id,
+      int main_frame_routing_id,
       Delegate* delegate,
       const std::string& partition_id,
       content::SessionStorageNamespace* session_storage_namespace);
   ~BackgroundContents() override;
 
   content::WebContents* web_contents() const { return web_contents_.get(); }
   virtual const GURL& GetURL() const;
 
   // content::WebContentsDelegate implementation:
   void CloseContents(content::WebContents* source) override;
@@ skipping 36 matching lines @@
   BackgroundContents* contents;
 
   // The name of the parent frame for these contents.
   const base::string16& frame_name;
 
   // The ID of the parent application (if any).
   const base::string16& application_id;
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_BACKGROUND_CONTENTS_H_