M20 Ash: Animate window header transition from active to inactive

ash/wm/frame_painter.h

Index: ash/wm/frame_painter.h
diff --git a/ash/wm/frame_painter.h b/ash/wm/frame_painter.h
index 324db1012c5988b06ee6e637ee0e46713024e277..ca6b47b007b6a610b0151586d7d917c3dfaf40b1 100644
--- a/ash/wm/frame_painter.h
+++ b/ash/wm/frame_painter.h
@@ -11,6 +11,9 @@
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"  // OVERRIDE
+#include "base/memory/scoped_ptr.h"
+#include "ui/base/animation/animation_delegate.h"
+#include "ui/gfx/rect.h"
 #include "ui/aura/window_observer.h"
 
 class SkBitmap;
@@ -20,10 +23,12 @@ class Window;
 namespace gfx {
 class Canvas;
 class Font;
-class Rect;
 class Point;
 class Size;
 }
+namespace ui {
+class SlideAnimation;
+}
 namespace views {
 class ImageButton;
 class NonClientFrameView;
@@ -36,7 +41,8 @@ namespace ash {
 // Helper class for painting window frames.  Exists to share code between
 // various implementations of views::NonClientFrameView.  Canonical source of
 // layout constants for Ash window frames.
-class ASH_EXPORT FramePainter : public aura::WindowObserver {
+class ASH_EXPORT FramePainter : public aura::WindowObserver,
+                                public ui::AnimationDelegate {
  public:
   // Opacity values for the window header in various states, from 0 to 255.
   static int kActiveWindowOpacity;
@@ -98,6 +104,9 @@ class ASH_EXPORT FramePainter : public aura::WindowObserver {
                                        intptr_t old) OVERRIDE;
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
 
+  // Overridden from ui::AnimationDelegate
+  virtual void AnimationProgressed(const ui::Animation* animation) OVERRIDE;
+
  private:
   // Sets the images for a button base on IDs from the |frame_| theme provider.
   void SetButtonImages(views::ImageButton* button,
@@ -131,6 +140,17 @@ class ASH_EXPORT FramePainter : public aura::WindowObserver {
   const SkBitmap* header_left_edge_;
   const SkBitmap* header_right_edge_;
 
+  // Bitmap and opacity last used for painting header.
+  const SkBitmap* previous_theme_frame_;
+  int previous_opacity_;
+
+  // Bitmap and opacity we are crossfading from.
+  const SkBitmap* crossfade_theme_frame_;
+  int crossfade_opacity_;
+
+  gfx::Rect header_frame_bounds_;
+  scoped_ptr<ui::SlideAnimation> crossfade_animation_;
+
   DISALLOW_COPY_AND_ASSIGN(FramePainter);
 };