Replace more ObserverList with base::ObserverList.

content/browser/appcache/appcache_service_impl.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_BROWSER_APPCACHE_APPCACHE_SERVICE_IMPL_H_
 #define CONTENT_BROWSER_APPCACHE_APPCACHE_SERVICE_IMPL_H_
 
 #include <map>
 #include <set>
 
@@ skipping 194 matching lines @@
   scoped_refptr<storage::QuotaManagerProxy> quota_manager_proxy_;
   PendingAsyncHelpers pending_helpers_;
   BackendMap backends_;  // One 'backend' per child process.
   // Context for use during cache updates.
   net::URLRequestContext* request_context_;
   // If true, nothing (not even session-only data) should be deleted on exit.
   bool force_keep_session_state_;
   base::Time last_reinit_time_;
   base::TimeDelta next_reinit_delay_;
   base::OneShotTimer<AppCacheServiceImpl> reinit_timer_;
-  ObserverList<Observer> observers_;
+  base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AppCacheServiceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_APPCACHE_APPCACHE_SERVICE_IMPL_H_