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

chrome/browser/chromeos/ui/accessibility_focus_ring.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_H_
 #define CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_H_
 
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
@@ skipping 54 matching lines @@
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 struct AccessibilityFocusRing {
   // Construct an AccessibilityFocusRing that outlines a rectangular object.
   static AccessibilityFocusRing CreateWithRect(
       const gfx::Rect& bounds, int margin);
 
+  // Returns a ring where 0.0 returns r1, 1.0 returns r2, and any number
+  // in-between interpolates linearly between them.
+  static AccessibilityFocusRing Interpolate(
+      const AccessibilityFocusRing& r1,
+      const AccessibilityFocusRing& r2,
+      double fraction);
+
   // Construct an AccessibilityFocusRing that outlines a paragraph-shaped
   // object.
   static AccessibilityFocusRing CreateWithParagraphShape(
       const gfx::Rect& top_line,
       const gfx::Rect& body,
       const gfx::Rect& bottom_line,
       int margin);
 
+  gfx::Rect GetBounds() const;
+
   gfx::Point points[36];
-  gfx::Rect GetBounds() const;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_H_