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

content/public/test/content_browser_test.cc

 // 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.
 
 #include "content/public/test/content_browser_test.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 143 matching lines @@
   }
 
   Shell::CloseAllWindows();
 }
 
 Shell* ContentBrowserTest::CreateBrowser() {
   return Shell::CreateNewWindow(
       ShellContentBrowserClient::Get()->browser_context(),
       GURL(url::kAboutBlankURL),
       NULL,
-      MSG_ROUTING_NONE,
       gfx::Size());
 }
 
 Shell* ContentBrowserTest::CreateOffTheRecordBrowser() {
   return Shell::CreateNewWindow(
       ShellContentBrowserClient::Get()->off_the_record_browser_context(),
       GURL(url::kAboutBlankURL),
       NULL,
-      MSG_ROUTING_NONE,
       gfx::Size());
 }
 
 }  // namespace content