mash: Migrate some system user files to common.

ash/root_window_controller.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 ASH_ROOT_WINDOW_CONTROLLER_H_
 #define ASH_ROOT_WINDOW_CONTROLLER_H_
 
 #include <map>
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/common/shell_observer.h"
-#include "ash/system/user/login_status.h"
 #include "base/macros.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/ui_base_types.h"
 
 class SkBitmap;
 
 namespace aura {
 class EventFilter;
 class Window;
@@ skipping 23 matching lines @@
 class RootWindowEventFilter;
 class ScopedCaptureClient;
 }
 
 namespace ash {
 class AshWindowTreeHost;
 class AlwaysOnTopController;
 class AnimatingDesktopController;
 class DesktopBackgroundWidgetController;
 class DockedWindowLayoutManager;
+enum class LoginStatus;

[msw, 2016/06/24 20:04:28]

WDYT about these forward decls? I'm on the fence...

[James Cook, 2016/06/24 20:18:53]

Either #include "ash/common/login_status.h" or forward declare, either way is
fine with me.

But let's not include "ash/system/user/login_status.h" just to get the enum.

[msw, 2016/06/24 20:26:46]

For sure, and I'd totally forward declare a class then include the header in the
cc file, but I'm just not used to doing the same with enums, and it feels a
little silly, but I'll leave the forward decls as they are in this patch set.

 class PanelLayoutManager;
 class RootWindowControllerCommon;
 class Shelf;
 class ShelfLayoutManager;
 class ShelfWidget;
 class StackingController;
 class StatusAreaWidget;
 class SystemBackgroundController;
 class SystemModalContainerLayoutManager;
 class SystemTray;
@@ skipping 269 matching lines @@
 
 // On classic ash, returns the RootWindowController for the given |root_window|.
 // On mus ash, returns the RootWindowController for the primary display.
 // See RootWindowController class comment above.
 ASH_EXPORT RootWindowController* GetRootWindowController(
     const aura::Window* root_window);
 
 }  // namespace ash
 
 #endif  // ASH_ROOT_WINDOW_CONTROLLER_H_