base: Add three helper functions to Values API.

chrome/browser/history/top_sites.cc

 // Copyright (c) 2011 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/history/top_sites.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/logging.h"
@@ skipping 346 matching lines @@
 }
 
 bool TopSites::HasBlacklistedItems() const {
   return !blacklist_->empty();
 }
 
 void TopSites::AddBlacklistedURL(const GURL& url) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   RemovePinnedURL(url);
-  Value* dummy = Value::CreateNullValue();
+  Value* dummy = base::NullValue();
   {
     DictionaryPrefUpdate update(profile_->GetPrefs(),
                                 prefs::kNTPMostVisitedURLsBlacklist);
     DictionaryValue* blacklist = update.Get();
     blacklist->SetWithoutPathExpansion(GetURLHash(url), dummy);
   }
 
   ResetThreadSafeCache();
   NotifyTopSitesChanged();
 }
@@ skipping 628 matching lines @@
   SetTopSites(pages);
 
   // Used only in testing.
   NotificationService::current()->Notify(
       chrome::NOTIFICATION_TOP_SITES_UPDATED,
       Source<TopSites>(this),
       Details<CancelableRequestProvider::Handle>(&handle));
 }
 
 }  // namespace history