Make TabContents ctor private; poke hole for existing callers.

chrome/browser/prerender/prerender_contents.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 "chrome/browser/prerender/prerender_contents.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
@@ skipping 306 matching lines @@
 
   // Everything after this point sets up the WebContents object and associated
   // RenderView for the prerender page. Don't do this for members of the
   // control group.
   if (is_control_group)
     return;
 
   prerendering_has_started_ = true;
 
   WebContents* new_contents = CreateWebContents(session_storage_namespace);
-  prerender_contents_.reset(new TabContents(new_contents));
+  prerender_contents_.reset(
+      TabContents::Factory::CreateTabContents(new_contents));
   content::WebContentsObserver::Observe(new_contents);
 
   tab_contents_delegate_.reset(new TabContentsDelegateImpl(this));
   new_contents->SetDelegate(tab_contents_delegate_.get());
 
   // Set the size of the prerender WebContents.
   prerender_contents_->web_contents()->GetView()->SizeContents(size_);
 
   // Register as an observer of the RenderViewHost so we get messages.
   render_view_host_observer_.reset(
@@ skipping 379 matching lines @@
 bool PrerenderContents::IsCrossSiteNavigationPending() const {
   if (!prerender_contents_.get() || !prerender_contents_->web_contents())
     return false;
   const WebContents* web_contents = prerender_contents_->web_contents();
   return (web_contents->GetSiteInstance() !=
           web_contents->GetPendingSiteInstance());
 }
 
 
 }  // namespace prerender