Adds filter support for offscreen canvas

third_party/WebKit/Source/core/css/CSSToLengthConversionData.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 62 matching lines @@
         ViewportSize(double width, double height) : m_size(width, height) { }
         explicit ViewportSize(const LayoutViewItem&);
 
         double width() const { return m_size.width(); }
         double height() const { return m_size.height(); }
     private:
         DoubleSize m_size;
     };
 
     CSSToLengthConversionData() { }
+    CSSToLengthConversionData(const ComputedStyle*, float zoom);
     CSSToLengthConversionData(const ComputedStyle*, const FontSizes&, const ViewportSize&, float zoom);
     CSSToLengthConversionData(const ComputedStyle* currStyle, const ComputedStyle* rootStyle, const LayoutViewItem&, float zoom);
 
     float zoom() const { return m_zoom; }
 
     float emFontSize() const { return m_fontSizes.em(); }
     float remFontSize() const;
     float exFontSize() const { return m_fontSizes.ex(); }
     float chFontSize() const { return m_fontSizes.ch(); }
 
@@ skipping 20 matching lines @@
 private:
     const ComputedStyle* m_style;
     FontSizes m_fontSizes;
     ViewportSize m_viewportSize;
     float m_zoom;
 };
 
 } // namespace blink
 
 #endif