2013-10-11  Sharath Kamath  <s.kamath@samsung.com>

        Support createBuffer with HTMLImageElement.

        Issue #153

        Restructure the createBuffer and createImage API
        adding a generic createBufferBase() API.

        Move generic code in createImage() to createImage2DBase().

        Reviewed by Antonio.

        Conformance test cases it affects :
        conformance/buffimgs/cl_context_createBuffer_with_HTMLImageElement.html
        conformance/buffimgs/cl_context_createImage_with_HTMLImageElement.html
        [https://github.com/SRA-SiliconValley/webkit-webcl-conformance]

        * Modules/webcl/WebCLContext.cpp:
        (WebCore::WebCLContext::createBufferBase):
        (WebCore::WebCLContext::createBuffer):
        (WebCore::WebCLContext::createImage2DBase):
        (WebCore::WebCLContext::createImage):
        * Modules/webcl/WebCLContext.h:
        * Modules/webcl/WebCLContext.idl: