Animate the accessibility focus ring and fix some minor visual issues.

chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_
 #define CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
+#include "base/time/time.h"
 #include "chrome/browser/chromeos/ui/accessibility_focus_ring_layer.h"
+#include "ui/compositor/compositor_animation_observer.h"
 #include "ui/gfx/rect.h"
 
+namespace ui {
+class Compositor;
+}
+
 namespace chromeos {
 
 // AccessibilityFocusRingController manages a custom focus ring (or multiple
 // rings) for accessibility.
-class AccessibilityFocusRingController : public FocusRingLayerDelegate {
+class AccessibilityFocusRingController
+    : public FocusRingLayerDelegate,
+      public ui::CompositorAnimationObserver {
  public:
   // Get the single instance of this class.
   static AccessibilityFocusRingController* GetInstance();
 
   // Draw a focus ring around the given set of rects, in global screen
   // coordinates.
   void SetFocusRing(const std::vector<gfx::Rect>& rects);
 
  protected:
   AccessibilityFocusRingController();
   virtual ~AccessibilityFocusRingController();
 
   // Given an unordered vector of bounding rectangles that cover everything
   // that currently has focus, populate a vector of one or more
   // AccessibilityFocusRings that surround the rectangles. Adjacent or
   // overlapping rectangles are combined first. This function is protected
   // so it can be unit-tested.
   void RectsToRings(const std::vector<gfx::Rect>& rects,
                     std::vector<AccessibilityFocusRing>* rings) const;
 
   virtual int GetMargin() const;
 
  private:
   // FocusRingLayerDelegate.
   virtual void OnDeviceScaleFactorChanged() OVERRIDE;
 
+  // CompositorAnimationObserver.
+  virtual void OnAnimationStep(base::TimeTicks timestamp) OVERRIDE;
+
   void Update();
 
   AccessibilityFocusRing RingFromSortedRects(
       const std::vector<gfx::Rect>& rects) const;
   void SplitIntoParagraphShape(
       const std::vector<gfx::Rect>& rects,
       gfx::Rect* top,
       gfx::Rect* middle,
       gfx::Rect* bottom) const;
   bool Intersects(const gfx::Rect& r1, const gfx::Rect& r2) const;
 
   std::vector<gfx::Rect> rects_;
+  std::vector<AccessibilityFocusRing> previous_rings_;
   std::vector<AccessibilityFocusRing> rings_;
-  scoped_ptr<AccessibilityFocusRingLayer> main_focus_ring_layer_;
-  std::vector<scoped_ptr<AccessibilityFocusRingLayer> > extra_layers_;
+  std::vector<scoped_ptr<AccessibilityFocusRingLayer> > layers_;
+  base::TimeTicks focus_change_time_;
+  ui::Compositor* compositor_;
 
   friend struct DefaultSingletonTraits<AccessibilityFocusRingController>;
 
   DISALLOW_COPY_AND_ASSIGN(AccessibilityFocusRingController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_