Change URL back to the previous one if the typed URL causes file download....

chrome/browser/tab_contents/tab_util.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/tab_contents/tab_util.h"
 
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
@@ skipping 11 matching lines @@
   if (!info)
     return false;
 
   *render_process_id = info->process_id;
   *render_view_id = info->route_id;
   return true;
 }
 
 TabContents* tab_util::GetTabContentsByID(int render_process_id,
                                           int render_view_id) {
+  // Ensures that that this method is only ever called on the UI thread.
+
+  // TODO(yuzo): Fix the callers and uncomment the following.
+  // DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
+  
   RenderViewHost* render_view_host =
       RenderViewHost::FromID(render_process_id, render_view_id);
   if (!render_view_host)
     return NULL;
 
   return render_view_host->delegate()->GetAsTabContents();
 }