Replace more ObserverList with base::ObserverList.

extensions/renderer/user_script_set.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 EXTENSIONS_RENDERER_USER_SCRIPT_SET_H_
 #define EXTENSIONS_RENDERER_USER_SCRIPT_SET_H_
 
 #include <set>
 #include <string>
 
@@ skipping 76 matching lines @@
   // Shared memory containing raw script data.
   scoped_ptr<base::SharedMemory> shared_memory_;
 
   // The set of all known extensions. Owned by the Dispatcher.
   const ExtensionSet* extensions_;
 
   // The UserScripts this injector manages.
   ScopedVector<UserScript> scripts_;
 
   // The associated observers.
-  ObserverList<Observer> observers_;
+  base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptSet);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_USER_SCRIPT_SET_H_