Replace more ObserverList with base::ObserverList.

components/signin/core/browser/signin_manager_base.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.
 //
 // The signin manager encapsulates some functionality tracking
 // which user is signed in.
 //
 // **NOTE** on semantics of SigninManager:
 //
 // Once a signin is successful, the username becomes "established" and will not
@@ skipping 121 matching lines @@
   // Sets the authenticated user's account id.
   void SetAuthenticatedAccountId(const std::string& account_id);
 
   // Used by subclass to clear the authenticated user instead of using
   // SetAuthenticatedAccountId, which enforces special preconditions due
   // to the fact that it is part of the public API and called by clients.
   void clear_authenticated_user() { authenticated_account_id_.clear(); }
 
   // List of observers to notify on signin events.
   // Makes sure list is empty on destruction.
-  ObserverList<Observer, true> observer_list_;
+  base::ObserverList<Observer, true> observer_list_;
 
   // Helper method to notify all registered diagnostics observers with.
   void NotifyDiagnosticsObservers(
       const signin_internals_util::TimedSigninStatusField& field,
       const std::string& value);
 
  private:
   friend class FakeSigninManagerBase;
   friend class FakeSigninManager;
 
   SigninClient* client_;
   AccountTrackerService* account_tracker_service_;
   bool initialized_;
 
   // Account id after successful authentication.
   std::string authenticated_account_id_;
 
   // The list of SigninDiagnosticObservers.
-  ObserverList<signin_internals_util::SigninDiagnosticsObserver, true>
+  base::ObserverList<signin_internals_util::SigninDiagnosticsObserver, true>
       signin_diagnostics_observers_;
 
   base::WeakPtrFactory<SigninManagerBase> weak_pointer_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninManagerBase);
 };
 
 #endif  // COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_MANAGER_BASE_H_