Give the main frame a RenderWidget.

content/browser/frame_host/render_frame_host_manager.h

Index: content/browser/frame_host/render_frame_host_manager.h
diff --git a/content/browser/frame_host/render_frame_host_manager.h b/content/browser/frame_host/render_frame_host_manager.h
index c8542adac119a8938afa8fc189ca7fdf7ef43f1d..9d3fd77a14fea4e5c2bc0d087aabcc8c38ae58fb 100644
--- a/content/browser/frame_host/render_frame_host_manager.h
+++ b/content/browser/frame_host/render_frame_host_manager.h
@@ -202,8 +202,8 @@ class CONTENT_EXPORT RenderFrameHostManager {
   ~RenderFrameHostManager();
 
   // For arguments, see WebContentsImpl constructor.
-  void Init(BrowserContext* browser_context,
-            SiteInstance* site_instance,
+  // TODO(dcheng): |site_instance| should probably be a const scoped_refptr<>&.

[ncarter (slow), 2015/09/03 20:24:37]

I think this is worth contemplating, but I don't think it's worth a TODO
comment.

[dcheng, 2015/09/03 21:29:24]

Comment removed.

+  void Init(SiteInstance* site_instance,
             int32 view_routing_id,
             int32 frame_routing_id,
             int32 widget_routing_id,