Always create FrameTreeNodes and RenderFrameHosts for every frame.

content/renderer/render_view_impl.h

Index: content/renderer/render_view_impl.h
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index 5f3e8912048421134259e0f6d3ef01ee53707e49..e8b0edafefd709cecab5bd47de26a62c18dada31 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -1381,7 +1381,8 @@ class CONTENT_EXPORT RenderViewImpl
 
   // Helper objects ------------------------------------------------------------
 
-  scoped_ptr<RenderFrameImpl> main_render_frame_;
+  // Deleted by RenderFrameImpl::frameDetach().
+  RenderFrameImpl* main_render_frame_;

[awong, 2013/11/22 01:07:15]

I think this still needs to be a scoped_ptr.  See comment in frameDetach()

[Charlie Reis, 2013/11/22 02:07:23]

I'm confused.  Are you referring to this comment?

  // If the frame does not have a parent, it is the main frame. The main
  // frame is owned by the containing RenderViewHost so it does not require
  // any cleanup here.

That comment isn't consistent with what I see in the debugger.  When closing a
tab with an iframe that is sharing a process with another tab, I see calls to
RenderFrameImpl::frameDetach for both the iframe and the main frame.

Indeed, the comments in RenderFrameImpl::frameDetach seem wrong, since
detachFromParent seems to be called for every frame.

 
   RendererWebCookieJarImpl cookie_jar_;