ash/wm: Remove dead code.

ui/views/widget/desktop_aura/desktop_dispatcher_client.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_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_DISPATCHER_CLIENT_H_
-#define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_DISPATCHER_CLIENT_H_
-
-#include "base/callback.h"
-#include "base/macros.h"
-#include "ui/views/views_export.h"
-#include "ui/wm/public/dispatcher_client.h"
-
-namespace views {
-
-// TODO(erg): I won't lie to you; I have no idea what this is or what it does.
-class VIEWS_EXPORT DesktopDispatcherClient
-    : public aura::client::DispatcherClient {
- public:
-  DesktopDispatcherClient();
-  ~DesktopDispatcherClient() override;
-
-  void PrepareNestedLoopClosures(base::MessagePumpDispatcher* dispatcher,
-                                 base::Closure* run_closure,
-                                 base::Closure* quit_closure) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(DesktopDispatcherClient);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_DISPATCHER_CLIENT_H_