Remove the MessageLoop::DestructionObserver from mojo bindings.

ash/common/cast_config_controller.h

 // Copyright 2016 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 ASH_COMMON_CAST_CONFIG_CONTROLLER_H_
 #define ASH_COMMON_CAST_CONFIG_CONTROLLER_H_
 
 #include <vector>
 
 #include "ash/public/interfaces/cast_config.mojom.h"
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 
 namespace ash {
 
 // There is a single CastConfigController which receives device
 // information. This observer interface sends that information to all the
 // TrayCast items--there is one per display.
 class CastConfigControllerObserver {
  public:
@@ skipping 37 matching lines @@
   mojom::CastConfigClientAssociatedPtr client_;
 
   base::ObserverList<CastConfigControllerObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(CastConfigController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_CAST_CONFIG_CONTROLLER_H_