Swap the main frame in --site-per-process mode too.

content/renderer/render_frame_impl.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/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 1194 matching lines @@
   // It is now safe to show modal dialogs again.
   // TODO(creis): Deal with modal dialogs from subframes.
   if (is_main_frame)
     render_view_->suppress_dialogs_until_swap_out_ = false;
 
   Send(new FrameHostMsg_SwapOut_ACK(routing_id_));
 
   // Now that all of the cleanup is complete and the browser side is notified,
   // start using the RenderFrameProxy, if one is created.
   if (proxy) {
-    if (!is_main_frame) {
+    if (!is_main_frame || is_site_per_process) {
       frame_->swap(proxy->web_frame());
 
       if (is_loading)
         proxy->OnDidStartLoading();
 
       if (is_site_per_process) {
         // TODO(nasko): delete the frame here, since we've replaced it with a
         // proxy.
       }
     }
@@ skipping 3691 matching lines @@
 #elif defined(ENABLE_BROWSER_CDMS)
         cdm_manager_,
 #endif
         this);
   }
 
   return cdm_factory_;
 }
 
 }  // namespace content