HTMLCanvasElement.toDataURL should use IDL 'any' to avoid using custom binding.

Source/core/html/HTMLCanvasElement.h

 /*
  * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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 90 matching lines @@
         reset();
     }
 
     // Called by HTMLCanvasElement's V8 bindings.
     ScriptValue getContext(ScriptState*, const String&, const CanvasContextCreationAttributes&);
     // Called by Document::getCSSCanvasContext as well as above getContext() variant.
     void getContext(const String&, const CanvasContextCreationAttributes&, CanvasRenderingContext2DOrWebGLRenderingContext&);
     bool isPaintable() const;
 
     static String toEncodingMimeType(const String& mimeType);
-    String toDataURL(const String& mimeType, const double* quality, ExceptionState&) const;
-    String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, 0, exceptionState); }
+    String toDataURL(const String& mimeType, const ScriptValue& qualityArgument, ExceptionState&) const;
+    String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, ScriptValue(), exceptionState); }
 
     // Used for rendering
     void didDraw(const FloatRect&);
     void notifyObserversCanvasChanged(const FloatRect&);
 
     void paint(GraphicsContext*, const LayoutRect&);
 
     GraphicsContext* drawingContext() const; // Deprecated: use drawingCanvas
     GraphicsContext* existingDrawingContext() const; // Deprecated: use existingDrawingCanvas
     SkCanvas* drawingCanvas() const;
@@ skipping 93 matching lines @@
     bool m_imageBufferIsClear;
     OwnPtr<ImageBuffer> m_imageBuffer;
     mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
 
     mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
 };
 
 } // namespace blink
 
 #endif // HTMLCanvasElement_h