drawFocusRing() function in CRC2D draws invalid focus ring.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 2265 matching lines @@
         }
     }
 }
 
 void CanvasRenderingContext2D::drawFocusRing(const Path& path)
 {
     GraphicsContext* c = drawingContext();
     if (!c)
         return;
 
+    // These should match the style defined in html.css.
+    Color focusRingColor = RenderTheme::theme().focusRingColor();
+    const int focusRingWidth = 5;
+    const int focusRingOutline = 0;
+
+    // We need to add focusRingWidth to dirtyRect.
+    StrokeData strokeData;
+    strokeData.setThickness(focusRingWidth);
+
     FloatRect dirtyRect;
-    if (!computeDirtyRect(path.boundingRect(), &dirtyRect))
+    if (!computeDirtyRect(path.strokeBoundingRect(strokeData), &dirtyRect))
         return;
 
     c->save();
     c->setAlphaAsFloat(1.0);
     c->clearShadow();
     c->setCompositeOperation(CompositeSourceOver, blink::WebBlendModeNormal);
-
-    // These should match the style defined in html.css.
-    Color focusRingColor = RenderTheme::theme().focusRingColor();
-    const int focusRingWidth = 5;
-    const int focusRingOutline = 0;
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
-
     c->restore();
 
     didDraw(dirtyRect);
 }
 
 } // namespace WebCore