Apply new MD shadows to CrOS tray bubbles.

ui/wm/core/shadow.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_H_
 #define UI_WM_CORE_SHADOW_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/wm/wm_export.h"
 
 namespace ui {
 class Layer;
 }  // namespace ui
 
 namespace wm {
 
 // Simple class that draws a drop shadow around content at given bounds.
 class WM_EXPORT Shadow : public ui::ImplicitAnimationObserver {
  public:
+  // TODO(estade): remove this enum and instead set elevation directly.
   enum Style {
     // Active windows have more opaque shadows, shifted down to make the window
     // appear "higher".
     STYLE_ACTIVE,
 
     // Inactive windows have less opaque shadows.
     STYLE_INACTIVE,
 
     // Small windows like tooltips and context menus have lighter, smaller
     // shadows.
@@ skipping 56 matching lines @@
 
   // Bounds of the content that the shadow encloses.
   gfx::Rect content_bounds_;
 
   DISALLOW_COPY_AND_ASSIGN(Shadow);
 };
 
 }  // namespace wm
 
 #endif  // UI_WM_CORE_SHADOW_H_