[Cleanup] Remove mac code from aura/ash/views

ui/aura/root_window_host_mac.h

-// Copyright (c) 2012 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 UI_AURA_ROOT_WINDOW_HOST_MAC_H_
-#define UI_AURA_ROOT_WINDOW_HOST_MAC_H_
-
-#include "base/basictypes.h"
-#include "base/event_types.h"
-
-namespace aura {
-
-// An interface establishing event dispatch from the Mac native window and the
-// Aura host.
-class RootWindowHostMacDelegate {
- public:
-  RootWindowHostMacDelegate();
-  virtual ~RootWindowHostMacDelegate();
-
-  // Route events from platform code to the RootWindowHost.
-  virtual void SendEvent(const base::NativeEvent& native_event) = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(RootWindowHostMacDelegate);
-};
-
-}  // namespace aura
-
-#endif  // UI_AURA_ROOT_WINDOW_HOST_MAC_H_