Add an adapter layer (WMHelper) between exo and ash.

components/exo/gamepad.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 COMPONENTS_EXO_GAMEPAD_H_
 #define COMPONENTS_EXO_GAMEPAD_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "components/exo/wm_helper.h"
 #include "device/gamepad/gamepad_data_fetcher.h"
 #include "ui/aura/client/focus_change_observer.h"
 
 namespace exo {
 class GamepadDelegate;
 
 using CreateGamepadDataFetcherCallback =
     base::Callback<std::unique_ptr<device::GamepadDataFetcher>()>;
 
 // This class represents one or more gamepads, it uses a background thread
 // for polling gamepad devices and notifies the GamepadDelegate of any
 // changes.
-class Gamepad : public aura::client::FocusChangeObserver {
+class Gamepad : public WMHelper::FocusObserver {
  public:
   // This class will post tasks to invoke the delegate on the thread runner
   // which is associated with the thread that is creating this instance.
   Gamepad(GamepadDelegate* delegate,
           base::SingleThreadTaskRunner* polling_task_runner);
   // Allows test cases to specify a CreateGamepadDataFetcherCallback that
   // overrides the default GamepadPlatformDataFetcher.
   Gamepad(GamepadDelegate* delegate,
           base::SingleThreadTaskRunner* polling_task_runner,
           CreateGamepadDataFetcherCallback create_fetcher_callback);
   ~Gamepad() override;
 
-  // Overridden aura::client::FocusChangeObserver:
+  // Overridden WMHelper::FocusObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
  private:
   class ThreadSafeGamepadChangeFetcher;
 
   // Processes updates of gamepad data and passes changes on to delegate.
   void ProcessGamepadChanges(const blink::WebGamepad new_pad);
 
   // Private implementation of methods and resources that are used on the
@@ skipping 10 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<Gamepad> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Gamepad);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_GAMEPAD_H_