Add UIControlsAsh that works with multiple root windows

ash/wm/window_properties.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_WM_WINDOW_PROPERTIES_H_
 #define ASH_WM_WINDOW_PROPERTIES_H_
 #pragma once
 
 #include "ash/wm/property_util.h"
 #include "ash/wm/shadow_types.h"
 #include "ui/aura/window.h"
 #include "ui/base/ui_base_types.h"
 
+namespace ui_controls {
+class UIControlsAura;
+}
+
 namespace ash {
 namespace internal {
 
 // Shell-specific window property keys.
 
 // Alphabetical sort.
 
 // Property set on all windows whose child windows' visibility changes are
 // animated.
 extern const aura::WindowProperty<bool>* const
     kChildWindowVisibilityChangesAnimatedKey;
 
 // Used to remember the show state before the window was minimized.
 extern const aura::WindowProperty<ui::WindowShowState>* const
     kRestoreShowStateKey;
 
 // A property key describing the drop shadow that should be displayed under the
 // window.  If unset, no shadow is displayed.
 extern const aura::WindowProperty<ShadowType>* const kShadowTypeKey;
 
+// Used to store a ui_controls for each root window.
+extern const aura::WindowProperty<ui_controls::UIControlsAura*>* const
+    kUIControlsKey;
+
 extern const aura::WindowProperty<WindowPersistsAcrossAllWorkspacesType>* const
     kWindowPersistsAcrossAllWorkspacesKey;
 
 // True if the window is controlled by the workspace manager.
 extern const aura::WindowProperty<bool>* const
     kWindowTrackedByWorkspaceKey;
 
 // Alphabetical sort.
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WINDOW_PROPERTIES_H_