Don't swap out the old RenderFrameHost until the new one commits.

content/browser/frame_host/navigator_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/browser/frame_host/navigator_impl.h"
 
 #include "base/command_line.h"
 #include "base/time/time.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
@@ skipping 355 matching lines @@
   if (delegate_)
     delegate_->AboutToNavigateRenderFrame(dest_render_frame_host);
 
   // WebContents uses this to fill LoadNotificationDetails when the load
   // completes, so that PerformanceMonitor that listens to the notification can
   // record the load time. PerformanceMonitor is no longer maintained.
   // TODO(ppi): make this go away.
   current_load_start_ = base::TimeTicks::Now();
 
   // Navigate in the desired RenderFrameHost.
+  // We can skip this step in the rare case that this is a transfer navigation
+  // which began in the chosen RenderFrameHost, since the request has already
+  // been issued.  In that case, simply resume the response.
   FrameMsg_Navigate_Params navigate_params;
   MakeNavigateParams(entry, *controller_, reload_type, navigation_start,
       &navigate_params);
-  dest_render_frame_host->Navigate(navigate_params);
+  bool is_transfer_to_same =
+      navigate_params.transferred_request_child_id != -1 &&
+      navigate_params.transferred_request_child_id ==
+          dest_render_frame_host->GetProcess()->GetID();
+  if (!is_transfer_to_same) {
+    dest_render_frame_host->Navigate(navigate_params);
+  } else {
+    // No need to navigate again.  Just resume the deferred request.
+    dest_render_frame_host->GetProcess()->ResumeDeferredNavigation(
+        GlobalRequestID(navigate_params.transferred_request_child_id,
+                        navigate_params.transferred_request_request_id));
+  }
 
   // Make sure no code called via RFH::Navigate clears the pending entry.
   CHECK_EQ(controller_->GetPendingEntry(), &entry);
 
   if (entry.GetPageID() == -1) {
     // HACK!!  This code suppresses javascript: URLs from being added to
     // session history, which is what we want to do for javascript: URLs that
     // do not generate content.  What we really need is a message from the
     // renderer telling us that a new page was not created.  The same message
     // could be used for mailto: URLs and the like.
@@ skipping 247 matching lines @@
 
     // Navigations in Web UI pages count as browser-initiated navigations.
     params.is_renderer_initiated = false;
   }
 
   if (delegate_)
     delegate_->RequestOpenURL(render_frame_host, params);
 }
 
 }  // namespace content