Always create FrameTreeNodes and RenderFrameHosts for every frame.

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/auto_reset.h"
@@ skipping 931 matching lines @@
   webview()->settings()->setAcceleratedCompositingForScrollableFramesEnabled(
       ShouldUseAcceleratedCompositingForScrollableFrames(device_scale_factor_));
   webview()->settings()->setCompositedScrollingForFramesEnabled(
       ShouldUseCompositedScrollingForFrames(device_scale_factor_));
 
   ApplyWebPreferences(webkit_preferences_, webview());
 
   main_render_frame_.reset(
       RenderFrameImpl::Create(this, params->main_frame_routing_id));
   // The main frame WebFrame object is closed by
-  // RenderViewImpl::frameDetached().
+  // RenderFrameImpl::frameDetached().
   webview()->setMainFrame(WebFrame::create(main_render_frame_.get()));
   main_render_frame_->MainWebFrameCreated(webview()->mainFrame());
   main_render_frame_->SetWebFrame(webview()->mainFrame());
 
   if (switches::IsTouchDragDropEnabled())
     webview()->settings()->setTouchDragDropEnabled(true);
 
   if (switches::IsTouchEditingEnabled())
     webview()->settings()->setTouchEditingEnabled(true);
 
@@ skipping 2109 matching lines @@
   // opener after hearing about it from the browser, and the browser does not
   // (yet) care about subframe openers.
   if (is_swapped_out_ || frame->parent())
     return;
 
   // Notify WebContents and all its swapped out RenderViews.
   Send(new ViewHostMsg_DidDisownOpener(routing_id_));
 }
 
 void RenderViewImpl::frameDetached(WebFrame* frame) {
+  // NOTE: We may get here for either the main frame or for subframes.  The
+  // RenderFrameImpl will be deleted immediately after this call for subframes
+  // but not for the main frame, which is owned by |main_render_frame_|.
+
   FOR_EACH_OBSERVER(RenderViewObserver, observers_, FrameDetached(frame));
 }
 
 void RenderViewImpl::willClose(WebFrame* frame) {
   FOR_EACH_OBSERVER(RenderViewObserver, observers_, FrameWillClose(frame));
 }
 
 void RenderViewImpl::didMatchCSS(
     WebFrame* frame,
     const WebVector<WebString>& newly_matching_selectors,
@@ skipping 3374 matching lines @@
   for (size_t i = 0; i < icon_urls.size(); i++) {
     WebURL url = icon_urls[i].iconURL();
     if (!url.isEmpty())
       urls.push_back(FaviconURL(url,
                                 ToFaviconType(icon_urls[i].iconType())));
   }
   SendUpdateFaviconURL(urls);
 }
 
 }  // namespace content