Fix prerender histograms for multiple prerender case.

chrome/browser/task_manager/task_manager_resource_providers.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/task_manager/task_manager_resource_providers.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 262 matching lines @@
   DCHECK(is_instant_preview_);
   is_instant_preview_ = false;
 }
 
 bool TaskManagerTabContentsResource::IsPrerendering() const {
   prerender::PrerenderManager* prerender_manager =
       prerender::PrerenderManagerFactory::GetForProfile(
           tab_contents_->profile());
   return prerender_manager &&
          prerender_manager->IsWebContentsPrerendering(
-             tab_contents_->web_contents());
+             tab_contents_->web_contents(), NULL);
 }
 
 bool TaskManagerTabContentsResource::HostsExtension() const {
   return tab_contents_->web_contents()->GetURL().SchemeIs(
       chrome::kExtensionScheme);
 }
 
 TaskManager::Resource::Type TaskManagerTabContentsResource::GetType() const {
   return HostsExtension() ? EXTENSION : RENDERER;
 }
@@ skipping 1389 matching lines @@
 
   return &resource_;
 }
 
 void TaskManagerBrowserProcessResourceProvider::StartUpdating() {
   task_manager_->AddResource(&resource_);
 }
 
 void TaskManagerBrowserProcessResourceProvider::StopUpdating() {
 }