Aura: New window shadows, desktop background debug toggle

ash/wm/shadow.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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_SHADOW_H_
 #define ASH_WM_SHADOW_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ash/ash_export.h"
+#include "ui/gfx/compositor/layer_animation_observer.h"
 #include "ui/gfx/rect.h"
 
 namespace ui {
 class Layer;
 }  // namespace ui
 
 namespace ash {
 namespace internal {
 
 class ImageGrid;
 
 // Simple class that draws a drop shadow around content at given bounds.
-class ASH_EXPORT Shadow {
+class ASH_EXPORT Shadow : public ui::ImplicitAnimationObserver {
  public:
+  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,
+  };
+
   Shadow();
-  ~Shadow();
+  virtual ~Shadow();
+
+  void Init();
 
   // Returns |image_grid_|'s ui::Layer.  This is exposed so it can be added to
   // the same layer as the content and stacked below it.  SetContentBounds()
   // should be used to adjust the shadow's size and position (rather than
   // applying transformations to this layer).
   ui::Layer* layer() const;
 
   const gfx::Rect& content_bounds() const { return content_bounds_; }
-
-  void Init();
+  Style style() const { return style_; }
 
   // Moves and resizes |image_grid_| to frame |content_bounds|.
   void SetContentBounds(const gfx::Rect& content_bounds);
 
+  // Sets the shadow's style, animating opacity as necessary.
+  void SetStyle(Style style);
+
+  // ui::ImplicitAnimationObserver overrides:
+  virtual void OnImplicitAnimationsCompleted() OVERRIDE;
+
  private:
+  // Updates the |image_grid_| images to the current |style_|.
+  void UpdateImagesForStyle();
+
+  // Updates the |image_grid_| bounds based on its image sizes and the
+  // current |content_bounds_|.
+  void UpdateImageGridBounds();
+
+  // The current style, set when the transition animation starts.
+  Style style_;
+
   scoped_ptr<ImageGrid> image_grid_;
 
   // Bounds of the content that the shadow encloses.
   gfx::Rect content_bounds_;
 
   DISALLOW_COPY_AND_ASSIGN(Shadow);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_SHADOW_H_