Replace more ObserverList with base::ObserverList.

content/browser/shared_worker/shared_worker_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_SHARED_WORKER_SHARED_WORKER_SERVICE_IMPL_H_
 #define CONTENT_BROWSER_SHARED_WORKER_SHARED_WORKER_SERVICE_IMPL_H_
 
 #include <set>
 
 #include "base/compiler_specific.h"
@@ skipping 150 matching lines @@
   // Function ptr to update worker dependency, tests may override this.
   UpdateWorkerDependencyFunc update_worker_dependency_;
 
   // Function ptr to increment worker ref count, tests may override this.
   static bool (*s_try_increment_worker_ref_count_)(int);
 
   WorkerHostMap worker_hosts_;
   PendingInstaneMap pending_instances_;
   int next_pending_instance_id_;
 
-  ObserverList<WorkerServiceObserver> observers_;
+  base::ObserverList<WorkerServiceObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedWorkerServiceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SHARED_WORKER_SHARED_WORKER_SERVICE_IMPL_H_