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

content/browser/frame_host/render_frame_host_manager_browsertest.cc

 // 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.
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
@@ skipping 1345 matching lines @@
   crash_observer.Wait();
 
   // Load the crash URL again but don't wait for any action.  If it is not
   // ignored this time, we will fail the WebUI CHECK in InitRenderView.
   shell()->LoadURL(GURL(kChromeUICrashURL));
 
   // Ensure that such URLs can still work as the initial navigation of a tab.
   // We postpone the initial navigation of the tab using an empty GURL, so that
   // we can add a watcher for crashes.
   Shell* shell2 = Shell::CreateNewWindow(
-      shell()->web_contents()->GetBrowserContext(), GURL(), NULL,
-      MSG_ROUTING_NONE, gfx::Size());
+      shell()->web_contents()->GetBrowserContext(), GURL(), NULL, gfx::Size());
   RenderProcessHostWatcher crash_observer2(
       shell2->web_contents(),
       RenderProcessHostWatcher::WATCH_FOR_PROCESS_EXIT);
   EXPECT_TRUE(
       NavigateToURLAndExpectNoCommit(shell2, GURL(kChromeUIKillURL)));
   crash_observer2.Wait();
 }
 
 // The test fails with Android ASAN with changes in v8 that seem unrelated.
 //   See http://crbug.com/428329.
@@ skipping 212 matching lines @@
   EXPECT_TRUE(ChildProcessSecurityPolicyImpl::GetInstance()->CanReadFile(
       shell()->web_contents()->GetRenderProcessHost()->GetID(), file_path));
 
   // Navigate to a same site page to trigger a PageState update and ensure the
   // renderer is not killed.
   EXPECT_TRUE(
       NavigateToURL(shell(), test_server()->GetURL("files/title2.html")));
 }
 
 }  // namespace content