mash: Migrate ScopedTargetRootWindow to //ash/common

ash/common/scoped_root_window_for_new_windows.h

 // Copyright 2013 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_SCOPED_TARGET_ROOT_WINDOW_H_
-#define ASH_SCOPED_TARGET_ROOT_WINDOW_H_
+#ifndef ASH_COMMON_SCOPED_ROOT_WINDOW_FOR_NEW_WINDOWS_H_
+#define ASH_COMMON_SCOPED_ROOT_WINDOW_FOR_NEW_WINDOWS_H_
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
 
-namespace aura {
-class Window;
-}
-
 namespace ash {
 
-// Constructing a ScopedTargetRootWindow allows temporarily
+class WmWindow;
+
+// Constructing a ScopedRootWindowForNewWindows allows temporarily
 // switching a target root window so that a new window gets created
 // in the same window where a user interaction happened.
 // An example usage is to specify the target root window when creating
 // a new window using launcher's icon.
-class ASH_EXPORT ScopedTargetRootWindow {
+class ASH_EXPORT ScopedRootWindowForNewWindows {
  public:
-  explicit ScopedTargetRootWindow(aura::Window* root_window);
-  ~ScopedTargetRootWindow();
+  explicit ScopedRootWindowForNewWindows(WmWindow* new_root);
+  ~ScopedRootWindowForNewWindows();
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(ScopedTargetRootWindow);
+  WmWindow* old_root_;

[James Cook, 2016/08/02 00:27:50]

I did this initially with base::AutoReset<> but the constructor looked a little
awkward to me, so I did it by hand.

[msw, 2016/08/02 01:04:50]

Acknowledged.

+
+  DISALLOW_COPY_AND_ASSIGN(ScopedRootWindowForNewWindows);
 };
 
 }  // namespace ash
 
-#endif  // ASH_SCOPED_TARGET_ROOT_WINDOW_H_
+#endif  // ASH_COMMON_SCOPED_ROOT_WINDOW_FOR_NEW_WINDOWS_H_