Make using WebContentsUserData simpler.

chrome/browser/ui/alternate_error_tab_observer.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/ui/alternate_error_tab_observer.h"
 
 #include "chrome/browser/google/google_util.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 
 using content::RenderViewHost;
 using content::WebContents;
 
-int AlternateErrorPageTabObserver::kUserDataKey;
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(AlternateErrorPageTabObserver)
 
 AlternateErrorPageTabObserver::AlternateErrorPageTabObserver(
     WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       profile_(Profile::FromBrowserContext(web_contents->GetBrowserContext())) {
   PrefService* prefs = profile_->GetPrefs();
   if (prefs) {
     pref_change_registrar_.Init(prefs);
     pref_change_registrar_.Add(prefs::kAlternateErrorPagesEnabled, this);
   }
@@ skipping 52 matching lines @@
     url = google_util::AppendGoogleLocaleParam(url);
     url = google_util::AppendGoogleTLDParam(profile_, url);
   }
   return url;
 }
 
 void AlternateErrorPageTabObserver::UpdateAlternateErrorPageURL(
     RenderViewHost* rvh) {
   rvh->SetAltErrorPageURL(GetAlternateErrorPageURL());
 }