globalCompositeOperation is ignored in stroke, strokeRect.

Source/platform/graphics/GraphicsContext.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 224 matching lines @@
     void strokeEllipse(const FloatRect&);
 
     void fillRect(const FloatRect&);
     void fillRect(const FloatRect&, const Color&);
     void fillRect(const FloatRect&, const Color&, CompositeOperator);
     void fillRoundedRect(const IntRect&, const IntSize& topLeft, const IntSize& topRight, const IntSize& bottomLeft, const IntSize& bottomRight, const Color&);
     void fillRoundedRect(const RoundedRect&, const Color&);
 
     void clearRect(const FloatRect&);
 
+    void strokeRect(const FloatRect&);
     void strokeRect(const FloatRect&, float lineWidth);
 
     void fillBetweenRoundedRects(const IntRect&, const IntSize& outerTopLeft, const IntSize& outerTopRight, const IntSize& outerBottomLeft, const IntSize& outerBottomRight,
         const IntRect&, const IntSize& innerTopLeft, const IntSize& innerTopRight, const IntSize& innerBottomLeft, const IntSize& innerBottomRight, const Color&);
     void fillBetweenRoundedRects(const RoundedRect&, const RoundedRect&, const Color&);
 
     void drawDisplayList(DisplayList*);
 
     void drawImage(Image*, const IntPoint&, CompositeOperator = CompositeSourceOver, RespectImageOrientationEnum = DoNotRespectImageOrientation);
     void drawImage(Image*, const IntRect&, CompositeOperator = CompositeSourceOver, RespectImageOrientationEnum = DoNotRespectImageOrientation);
@@ skipping 253 matching lines @@
     bool m_updatingControlTints : 1;
     bool m_accelerated : 1;
     bool m_isCertainlyOpaque : 1;
     bool m_printing : 1;
     bool m_antialiasHairlineImages : 1;
 };
 
 } // namespace WebCore
 
 #endif // GraphicsContext_h