2014-01-27 Antonio Gomes <a1.gomes@sisa.samsung.com>
        WebCLCommandQueue::enqueueWaitForEvents can take user events
        Issue #435

        Reviewed by Igor.

        As per http://www.khronos.org/bugzilla/show_bug.cgi?id=1094
        (WebCLCommandQueue::enqueueWaitForEvents should not take WebCLUserEvent's),
        the API can take user event.

        It was identified as a bug in the OpenCL spec.

        * Modules/webcl/WebCLCommandQueue.cpp:
        (WebCore::WebCLCommandQueue::enqueueWaitForEvents):