Make using WebContentsUserData simpler.

chrome/browser/automation/automation_tab_helper.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/automation/automation_tab_helper.h"
 
 #include <algorithm>
 
 #include "chrome/common/automation_messages.h"
 #include "content/public/browser/web_contents.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_macros.h"
 #include "ui/gfx/size.h"
 
 using content::WebContents;
 
-int AutomationTabHelper::kUserDataKey;
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(AutomationTabHelper)
 
 TabEventObserver::TabEventObserver() { }
 
 TabEventObserver::~TabEventObserver() {
   for (size_t i = 0; i < event_sources_.size(); ++i) {
     if (event_sources_[i])
       event_sources_[i]->RemoveObserver(this);
   }
 }
 
@@ skipping 137 matching lines @@
   // It is possible that we did not track the redirect becasue it had a non-zero
   // delay. See the comment in |OnWillPerformClientRedirect|.
   if (iter != pending_client_redirects_.end()) {
     pending_client_redirects_.erase(iter);
     if (!has_pending_loads()) {
       FOR_EACH_OBSERVER(TabEventObserver, observers_,
                         OnNoMorePendingLoads(web_contents()));
     }
   }
 }