Reviewed by Maciej.

        http://bugzilla.opendarwin.org/show_bug.cgi?id=8958
        Should be able to have custom implementations for JS methods
        
        * DerivedSources.make:
        * WebCore.xcodeproj/project.pbxproj:
        * bindings/js/JSCanvasRenderingContext2DBase.cpp: Removed.
        * bindings/js/JSCanvasRenderingContext2DBase.h: Removed.
        * bindings/js/JSCanvasRenderingContext2DCustom.cpp: Added.
        Remove JSCanvasRenderingContext2DBase and add 
        JSCanvasRenderingContext2DCustom with custom implementations.
        
        (WebCore::toJS):
        (WebCore::toHTMLCanvasStyle):
        (WebCore::JSCanvasRenderingContext2D::strokeStyle):
        (WebCore::JSCanvasRenderingContext2D::setStrokeStyle):
        (WebCore::JSCanvasRenderingContext2D::fillStyle):
        (WebCore::JSCanvasRenderingContext2D::setFillStyle):
        (WebCore::JSCanvasRenderingContext2D::setFillColor):
        (WebCore::JSCanvasRenderingContext2D::setStrokeColor):
        (WebCore::JSCanvasRenderingContext2D::strokeRect):
        (WebCore::JSCanvasRenderingContext2D::drawImage):
        (WebCore::JSCanvasRenderingContext2D::drawImageFromRect):
        (WebCore::JSCanvasRenderingContext2D::setShadow):
        (WebCore::JSCanvasRenderingContext2D::createPattern):
        Move implementations from JSCanvasRenderingContext2DBase.
        
        * bindings/scripts/CodeGeneratorJS.pm:
        Add new "Custom" extended attribute for functions and attributes. When a function or 
        attribute has this attribute, a custom implementation is called instead of calling down to
        the DOM object.
        
        * html/CanvasRenderingContext2D.idl:
        Add bunch of custom attributes and functions.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@14449 268f45cc-cd09-0410-ab3c-d52691b4dbfc