Create a new RenderFrameHost per child frame when --site-per-process is enabled.

content/browser/web_contents/render_view_host_manager.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/browser/web_contents/render_view_host_manager.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 66 matching lines @@
                                  int routing_id,
                                  int main_frame_routing_id) {
   // Create a RenderViewHost, once we have an instance.  It is important to
   // immediately give this SiteInstance to a RenderViewHost so that it is
   // ref counted.
   if (!site_instance)
     site_instance = SiteInstance::Create(browser_context);
   render_view_host_ = static_cast<RenderViewHostImpl*>(
       RenderViewHostFactory::Create(
           site_instance, render_view_delegate_, render_widget_delegate_,
-          routing_id, main_frame_routing_id, false, delegate_->IsHidden()));
+          routing_id, main_frame_routing_id, false,
+          delegate_->IsHidden()));
+  render_view_host_->AttachToFrameTree();
 
   // Keep track of renderer processes as they start to shut down or are
   // crashed/killed.
   registrar_.Add(this, NOTIFICATION_RENDERER_PROCESS_CLOSED,
                  NotificationService::AllSources());
   registrar_.Add(this, NOTIFICATION_RENDERER_PROCESS_CLOSING,
                  NotificationService::AllSources());
 }
 
 RenderViewHostImpl* RenderViewHostManager::current_host() const {
@@ skipping 632 matching lines @@
     if (will_focus_location_bar)
       delegate_->SetFocusToLocationBar(false);
     return;
   }
 
   // Remember if the page was focused so we can focus the new renderer in
   // that case.
   bool focus_render_view = !will_focus_location_bar &&
       render_view_host_->GetView() && render_view_host_->GetView()->HasFocus();
 
-  // Swap in the pending view and make it active.
+  // Swap in the pending view and make it active. Also ensure the FrameTree
+  // stays in sync.
   RenderViewHostImpl* old_render_view_host = render_view_host_;
   render_view_host_ = pending_render_view_host_;
   pending_render_view_host_ = NULL;
+  render_view_host_->AttachToFrameTree();
 
   // The process will no longer try to exit, so we can decrement the count.
   render_view_host_->GetProcess()->RemovePendingView();
 
   // Hide the old view before showing the new view.  This has the potential to
   // reduce peak memory usage, by freeing up a large resource before allocating
   // a new large resource.
   if (old_render_view_host->GetView()) {
     old_render_view_host->GetView()->Hide();
     old_render_view_host->WasSwappedOut();
@@ skipping 293 matching lines @@
 RenderViewHostImpl* RenderViewHostManager::GetSwappedOutRenderViewHost(
     SiteInstance* instance) {
   RenderViewHostMap::iterator iter = swapped_out_hosts_.find(instance->GetId());
   if (iter != swapped_out_hosts_.end())
     return iter->second;
 
   return NULL;
 }
 
 }  // namespace content