Revert of mash: Fix MusPropertyMirrorAsh for owned properties; add test.

ash/public/cpp/mus_property_mirror_ash.h

-// Copyright 2017 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_PUBLIC_CPP_MUS_PROPERTY_MIRROR_H_
-#define ASH_PUBLIC_CPP_MUS_PROPERTY_MIRROR_H_
-
-#include "base/macros.h"
-#include "ui/views/mus/mus_property_mirror.h"
-
-namespace ash {
-
-// Relays aura content window properties to its root window (the mash frame).
-// Ash relies on various window properties for frame titles, shelf items, etc.
-// These properties are read from the client's root, not child content windows.
-class MusPropertyMirrorAsh : public views::MusPropertyMirror {
- public:
-  MusPropertyMirrorAsh();
-  ~MusPropertyMirrorAsh() override;
-
-  // MusPropertyMirror:
-  void MirrorPropertyFromWidgetWindowToRootWindow(aura::Window* window,
-                                                  aura::Window* root_window,
-                                                  const void* key) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(MusPropertyMirrorAsh);
-};
-
-}  // namespace ash
-
-#endif  // ASH_PUBLIC_CPP_MUS_PROPERTY_MIRROR_H_