2014-02-25  Sharath Kamath  <s.kamath@samsung.com>

        Calculate rowPitch when hostPtr != NULL and rowPitch == 0

        Fixed #456

        Reviewed by Antonio Gomes.

        Spotted by Anthony Liot.

        This fixes a translated demo.

        Validating the use sent rowPitch value, to avoid out of bound
        access of the hostPtr.
        Also validating the value as per specification conditions.

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