mash: improves browser frame decorations

ui/wm/core/shadow_types.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 UI_WM_CORE_SHADOW_TYPES_H_
 #define UI_WM_CORE_SHADOW_TYPES_H_
 
 #include "ui/aura/window.h"
 #include "ui/wm/wm_export.h"
 
-namespace aura {
-class Window;
-}
-
 namespace wm {
 
 // Different types of drop shadows that can be drawn under a window by the
 // shell. Used as a value for the kShadowTypeKey property. The integer value of
 // each entry is directly used for determining the size of the shadow.
 enum class ShadowElevation {
   // Indicates an elevation should be chosen based on the window. This is the
   // default.
   DEFAULT = -1,
   NONE = 0,
   SMALL = 6,
   MEDIUM = 8,
   LARGE = 24,
 };
 
 WM_EXPORT void SetShadowElevation(aura::Window* window,
                                   ShadowElevation elevation);
 
 // Returns true if |value| is a valid element of ShadowElevation elements.
 WM_EXPORT bool IsValidShadowElevation(int64_t value);
 
 // A property key describing the drop shadow that should be displayed under the
 // window. A null value is interpreted as using the default.
 WM_EXPORT extern const aura::WindowProperty<ShadowElevation>* const
     kShadowElevationKey;
 
 }  // namespace wm
 
 #endif  // UI_WM_CORE_SHADOW_TYPES_H_