2014-05-15  Sharath Kamath  <s.kamath@samsung.com>

        Update the cache with actual used value of RowPitch.

        Issue #522

        Reviewed by NOBODY (OOPS!).

        Test case cl_image_getInfo.html in conformance test suite.

        As OpenCL uses the default value to read the hostPtr when user sends a "0"
        rowPitch, getInfo needs to be updated with this default value instead of "0".

        So querying the same information in constructor of WebCLImage() and caching the
        same in the imageDescriptior object.

        * Modules/webcl/WebCLContext.cpp:
        (WebCore::WebCLContext::createImage):