https://bugs.webkit.org/show_bug.cgi?id=122043

Reviewed by Eric Carlson.

Source/WebCore:

Test: media/track/audio-track.html

Add a new class AudioTrackPrivateAVF and subclass AudioTrackPrivateAVFObjC
which are backed by a AVPlayerItemTrack. Create one of these tracks when
we are notified that the list of available tracks has changed.

* WebCore.xcodeproj/project.pbxproj:
* html/track/AudioTrack.cpp:
(WebCore::AudioTrack::setEnabled): Pass through to the AudioTrackPrivate
    so that the underlying media track can be (dis|en)abled.
* platform/graphics/avfoundation/AudioTrackPrivateAVF.h: Added.
(WebCore::AudioTrackPrivateAVF::kind): Simple getter.
(WebCore::AudioTrackPrivateAVF::id): Ditto.
(WebCore::AudioTrackPrivateAVF::label): Ditto.
(WebCore::AudioTrackPrivateAVF::language): Ditto.
(WebCore::AudioTrackPrivateAVF::setKind): Simple Setter.
(WebCore::AudioTrackPrivateAVF::setId): Ditto.
(WebCore::AudioTrackPrivateAVF::setLabel): Ditto.
(WebCore::AudioTrackPrivateAVF::setLanguage): Ditto.
(WebCore::AudioTrackPrivateAVF::AudioTrackPrivateAVF): Simple constructor.
* platform/graphics/avfoundation/objc/AudioTrackPrivateAVFObjC.h: Added.
(WebCore::AudioTrackPrivateAVFObjC::create): Simple factory.
(WebCore::AudioTrackPrivateAVFObjC::playerItemTrack): Simple getter.
* platform/graphics/avfoundation/objc/AudioTrackPrivateAVFObjC.mm: Added.
(WebCore::AudioTrackPrivateAVFObjC::AudioTrackPrivateAVFObjC): Call resetPropertiesFromTrack.
(WebCore::AudioTrackPrivateAVFObjC::resetPropertiesFromTrack): Fill out the values from
    the associated AVPlayerItemTrack and its AVAssetTrack.
(WebCore::AudioTrackPrivateAVFObjC::setPlayerItemTrack): Call resetPropertiesFromTrack.
(WebCore::AudioTrackPrivateAVFObjC::setEnabled): (En|Dis)able the AVPlayerItemTrack.
(WebCore::AudioTrackPrivateAVFObjC::languageForAVAssetTrack): Refactored from
    MediaPlayerPrivateAVFoundationObjC::languageOfPrimaryAudioTrack.
* platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.h:
* platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:
(WebCore::MediaPlayerPrivateAVFoundationObjC::tracksChanged): Determine which tracks
    have been added or removed and notify the clients accordingly.
(WebCore::MediaPlayerPrivateAVFoundationObjC::languageOfPrimaryAudioTrack): Refactor into
    AudioTrackPrivateAVFObjC::languageForAVAssetTrack.

LayoutTests:

* media/track/audio-track-expected.txt: Added.
* media/track/audio-track.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@156652 268f45cc-cd09-0410-ab3c-d52691b4dbfc