Always create FrameTreeNodes and RenderFrameHosts for every frame.

content/browser/frame_host/frame_tree.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 "content/browser/frame_host/frame_tree.h"
 
 #include <queue>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 92 matching lines @@
                                          const std::string& frame_name) {
   FrameTreeNode* parent = FindByFrameID(parent_frame_id);
   // TODO(ajwong): Should the renderer be killed here? Would there be a race on
   // shutdown that might make this case possible?
   if (!parent)
     return NULL;
 
   scoped_ptr<FrameTreeNode> node(new FrameTreeNode(
       this, parent->navigator(), render_frame_delegate_, render_view_delegate_,
       render_widget_delegate_, manager_delegate_, frame_id, frame_name));
-  RenderFrameHostImpl* render_frame = node->current_frame_host();
+  FrameTreeNode* node_ptr = node.get();
+  // AddChild is what creates the RenderFrameHost.
   parent->AddChild(node.Pass(), frame_routing_id);
-  return render_frame;
+  return node_ptr->current_frame_host();
 }
 
 void FrameTree::RemoveFrame(RenderFrameHostImpl* render_frame_host,
                             int64 parent_frame_id,
                             int64 frame_id) {
   // If switches::kSitePerProcess is not specified, then the FrameTree only
   // contains a node for the root element. However, even in this case
   // frame detachments need to be broadcast outwards.
   //
   // TODO(ajwong): Move this below the |parent| check after the FrameTree is
@@ skipping 108 matching lines @@
   }
 }
 
 FrameTreeNode* FrameTree::FindByFrameID(int64 frame_id) {
   FrameTreeNode* node = NULL;
   ForEach(base::Bind(&FrameTreeNodeForFrameId, frame_id, &node));
   return node;
 }
 
 }  // namespace content