Give the main frame a RenderWidget.

chrome/browser/android/document/document_web_contents_delegate.h

 // Copyright 2015 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_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_
 #define CHROME_BROWSER_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_
 
 #include "components/web_contents_delegate_android/web_contents_delegate_android.h"
 
 // Stub WebContentsDelegateAndroid that is meant to be a temporary substitute
@@ skipping 18 matching lines @@
   // Overridden from WebContentsDelegate.
   void AddNewContents(content::WebContents* source,
                       content::WebContents* new_contents,
                       WindowOpenDisposition disposition,
                       const gfx::Rect& initial_pos,
                       bool user_gesture,
                       bool* was_blocked) override;
   void CloseContents(content::WebContents* source) override;
   bool ShouldCreateWebContents(
       content::WebContents* web_contents,
-      int route_id,
-      int main_frame_route_id,
+      int32 route_id,

[sky, 2015/10/22 23:05:47]

int32->int32_t (the non _t types are deprecated, see comment in
base/basictypes.h). I'm only commenting on this here, no doubt you'll need to
update a bunch of places.

[dcheng, 2015/10/22 23:29:44]

This was intentional, to keep code in //content consistent (this code lives next
to a bunch of unchanged code that uses int32). If you feel strongly, I can
update.

+      int32 main_frame_route_id,
+      int32 main_frame_widget_route_id,
       WindowContainerType window_container_type,
       const std::string& frame_name,
       const GURL& target_url,
       const std::string& partition_id,
       content::SessionStorageNamespace* session_storage_namespace) override;
 };
 
 #endif  // CHROME_BROWSER_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_