2014-01-24  Sharath Kamath  <s.kamath@samsung.com>

        Incorrect event hadnling in WebCLEvent related class.

        Issue #431

        Reviewed by NOBODY (OOPS!).

        Mainly fixes minor issues to assure implementation is in par with
        specification and conformance.
        Does not change behaviour with WebCLUserEvent by these API's.

        Conformance test cases:
        [https://github.com/SRA-SiliconValley/webkit-webcl-conformance]
        conformance/bindingTesting/eventsAndCallbacks/cl_webcl_waitForEvents.html
        conformance/bindingTesting/queues/cl_commandQueue_enqueueWaitForEvents.html
        conformance/bindingTesting/queues/cl_commandQueue_enqueueBarrier.html

        * Modules/webcl/WebCL.cpp:
        (WebCore::WebCL::waitForEvents):
        * Modules/webcl/WebCLCommandQueue.cpp:
        (WebCore::WebCLCommandQueue::enqueueMarker):