Reviewed by Alp Toker.

        http://bugs.webkit.org/show_bug.cgi?id=16145
        [gtk] Implement media support in GTK backend

        This implements the media tags of HTML5 on the GTK+ port based on the 
        Mac port. Media tests pass although some tests required a small modifications: 
        As per the HTML5 spec, the loading of the clip should start only after 
        all script are done.  But in the case of the tests, the loading starts 
        before some callbacks get registered.  This has been discussed with 
        Antti Koivisto, and the tests should be updated.

        There is only one known issue: one time in 10 tries, loading a buffered 
        clip will never end buffering.  The buffering will stall at 97% for no 
        apparent reasons.  Reloading the page usually works around the problem.
        On the GStreamer side, some codecs don't return correct values, therefore
        they make the tests fail.  For instance H.264 will make the video-end 
        test fail.  This should be fixed in GStreamer 0.10.15.

        This version displays video in a pop up window.  A place holder is drawn
        on the page where the video should appear.

        By default, it is turned off in WebCore.pro until GStreamer/X
        detection issues are sorted out.

        * WebCore.pro:
        Disable video for now
        * platform/Logging.cpp:
        (WebCore::):
        * platform/Logging.h:
        Added a logging level for Media stuff
        * platform/graphics/Movie.cpp:
        * platform/graphics/gtk/MoviePrivateGStreamer.cpp: Added.
        (WebCore::moviePrivateErrorCallback):
        (WebCore::moviePrivateEOSCallback):
        (WebCore::moviePrivateStateCallback):
        (WebCore::moviePrivateBufferingCallback):
        (WebCore::moviePrivateWindowIDCallback):
        (WebCore::MoviePrivate::MoviePrivate):
        (WebCore::MoviePrivate::~MoviePrivate):
        (WebCore::MoviePrivate::load):
        (WebCore::MoviePrivate::play):
        (WebCore::MoviePrivate::pause):
        (WebCore::MoviePrivate::duration):
        (WebCore::MoviePrivate::currentTime):
        (WebCore::MoviePrivate::seek):
        (WebCore::MoviePrivate::setEndTime):
        (WebCore::MoviePrivate::addCuePoint):
        (WebCore::MoviePrivate::removeCuePoint):
        (WebCore::MoviePrivate::clearCuePoints):
        (WebCore::MoviePrivate::startCuePointTimerIfNeeded):
        (WebCore::MoviePrivate::cancelSeek):
        (WebCore::MoviePrivate::cuePointTimerFired):
        (WebCore::MoviePrivate::paused):
        (WebCore::MoviePrivate::seeking):
        (WebCore::MoviePrivate::naturalSize):
        (WebCore::MoviePrivate::hasVideo):
        (WebCore::MoviePrivate::setVolume):
        (WebCore::MoviePrivate::setMuted):
        (WebCore::MoviePrivate::setRate):
        (WebCore::MoviePrivate::dataRate):
        (WebCore::MoviePrivate::networkState):
        (WebCore::MoviePrivate::readyState):
        (WebCore::MoviePrivate::maxTimeBuffered):
        (WebCore::MoviePrivate::maxTimeSeekable):
        (WebCore::MoviePrivate::maxTimeLoaded):
        (WebCore::MoviePrivate::bytesLoaded):
        (WebCore::MoviePrivate::totalBytesKnown):
        (WebCore::MoviePrivate::totalBytes):
        (WebCore::MoviePrivate::cancelLoad):
        (WebCore::MoviePrivate::updateStates):
        (WebCore::MoviePrivate::loadStateChanged):
        (WebCore::MoviePrivate::rateChanged):
        (WebCore::MoviePrivate::sizeChanged):
        (WebCore::MoviePrivate::timeChanged):
        (WebCore::MoviePrivate::volumeChanged):
        (WebCore::MoviePrivate::didEnd):
        (WebCore::MoviePrivate::loadingFailed):
        (WebCore::MoviePrivate::setRect):
        (WebCore::MoviePrivate::setVisible):
        (WebCore::MoviePrivate::paint):
        (WebCore::MoviePrivate::getSupportedTypes):
        (WebCore::MoviePrivate::createGSTPlayBin):
        * platform/graphics/gtk/MoviePrivateGStreamer.h: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@28389 268f45cc-cd09-0410-ab3c-d52691b4dbfc