Revert of ash/mash: Add a mus-client that sets up ash to provide the system ui for mash.

ash/mus/sysui_application.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_MUS_SYSUI_APPLICATION_H_
-#define ASH_MUS_SYSUI_APPLICATION_H_
-
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "mojo/services/tracing/public/cpp/tracing_impl.h"
-#include "mojo/shell/public/cpp/shell_client.h"
-
-namespace ash {
-namespace sysui {
-
-class AshInit;
-
-class SysUIApplication : public mojo::ShellClient {
- public:
-  SysUIApplication();
-  ~SysUIApplication() override;
-
- private:
-  // mojo::ShellClient:
-  void Initialize(mojo::Shell* shell,
-                  const std::string& url,
-                  uint32_t id) override;
-
-  mojo::TracingImpl tracing_;
-  scoped_ptr<AshInit> ash_init_;
-
-  DISALLOW_COPY_AND_ASSIGN(SysUIApplication);
-};
-
-}  // namespace sysui
-}  // namespace ash
-
-#endif  // ASH_MUS_SYSUI_APPLICATION_H_