Reviewed by Tony Gentilcore.

        Introduce HTML5 track list objects.
        https://bugs.webkit.org/show_bug.cgi?id=60184

        Introduce the TrackList, MultipleTrackList and ExclusiveTrackList objects
        for their use in the MediaStream API and the HTML Media Element.
        Current spec: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-iframe-element.html#tracklist

        The Media Stream API will test this feature in the bug 56587.
        More tests related to the HTML Media Element may be added later.

        * CMakeLists.txt:
        * CodeGenerators.pri:
        * DerivedSources.cpp:
        * DerivedSources.make:
        * GNUmakefile.list.am:
        * WebCore.gypi:
        * WebCore.pro:
        * WebCore.vcproj/WebCore.vcproj:
        * WebCore.xcodeproj/project.pbxproj:
        * bindings/js/JSEventTarget.cpp:
        (WebCore::toJS):
        * bindings/v8/V8DOMWrapper.cpp:
        (WebCore::V8DOMWrapper::convertEventTargetToV8Object):
        * dom/DOMAllInOne.cpp:
        * dom/EventTarget.cpp:
        (WebCore::EventTarget::toTrackList):
        (WebCore::EventTarget::toMultipleTrackList):
        (WebCore::EventTarget::toExclusiveTrackList):
        * dom/EventTarget.h:
        * dom/ExclusiveTrackList.cpp: Added.
        (WebCore::ExclusiveTrackList::create):
        (WebCore::ExclusiveTrackList::ExclusiveTrackList):
        (WebCore::ExclusiveTrackList::~ExclusiveTrackList):
        (WebCore::ExclusiveTrackList::clear):
        (WebCore::ExclusiveTrackList::select):
        (WebCore::ExclusiveTrackList::toExclusiveTrackList):
        * dom/ExclusiveTrackList.h: Added.
        (WebCore::ExclusiveTrackList::selectedIndex):
        * dom/ExclusiveTrackList.idl: Added.
        * dom/MultipleTrackList.cpp: Added.
        (WebCore::MultipleTrackList::create):
        (WebCore::MultipleTrackList::MultipleTrackList):
        (WebCore::MultipleTrackList::~MultipleTrackList):
        (WebCore::MultipleTrackList::clear):
        (WebCore::MultipleTrackList::isEnabled):
        (WebCore::MultipleTrackList::enable):
        (WebCore::MultipleTrackList::disable):
        (WebCore::MultipleTrackList::toMultipleTrackList):
        * dom/MultipleTrackList.h: Added.
        * dom/MultipleTrackList.idl: Added.
        * dom/TrackList.cpp: Added.
        (WebCore::Track::create):
        (WebCore::Track::Track):
        (WebCore::TrackList::create):
        (WebCore::TrackList::TrackList):
        (WebCore::TrackList::~TrackList):
        (WebCore::TrackList::length):
        (WebCore::TrackList::checkIndex):
        (WebCore::TrackList::getID):
        (WebCore::TrackList::getKind):
        (WebCore::TrackList::getLabel):
        (WebCore::TrackList::getLanguage):
        (WebCore::TrackList::clear):
        (WebCore::TrackList::postChangeEvent):
        (WebCore::TrackList::dispatchChangeEvent):
        (WebCore::TrackList::toTrackList):
        (WebCore::TrackList::scriptExecutionContext):
        (WebCore::TrackList::eventTargetData):
        (WebCore::TrackList::ensureEventTargetData):
        * dom/TrackList.h: Added.
        (WebCore::Track::id):
        (WebCore::Track::kind):
        (WebCore::Track::label):
        (WebCore::Track::language):
        (WebCore::TrackList::DispatchTask::create):
        (WebCore::TrackList::DispatchTask::performTask):
        (WebCore::TrackList::DispatchTask::DispatchTask):
        (WebCore::TrackList::refEventTarget):
        (WebCore::TrackList::derefEventTarget):
        * dom/TrackList.idl: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@87293 268f45cc-cd09-0410-ab3c-d52691b4dbfc