<track> element's mode set to "disabled" after load although it was explicitly set...

<track> element's mode set to "disabled" after load although it was explicitly set to "hidden"
https://bugs.webkit.org/show_bug.cgi?id=105536

Source/WebCore:

Remove all concept of "showing by default". This means removing the showingByDefault()
and setShowingByDefault() methods on TextTrack. As I was going  through this code,
I also noticed that in HTMLMediaElement::configureTextTrackGroup(), we would set
defaultTrack to textTrack.get() even though defaultTrack was created to be a RefPtr<TextTrack>.

As a result, we can now pass an additional 8 tests from the Opera-submitted test suite:

LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html
LayoutTests/media/track/opera/interfaces/TextTrack/removeCue.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/endTime.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/startTime.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/align.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/id.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/pauseOnExit.html
LayoutTests/media/track/opera/interfaces/TextTrackCue/track.html

Patch by Antoine Quint <graouts@apple.com> on 2013-01-08
Reviewed by Eric Carlson.

* html/HTMLMediaElement.cpp:
(WebCore::HTMLMediaElement::configureTextTrackGroup):
(WebCore::HTMLMediaElement::toggleTrackAtIndex):
* html/track/TextTrack.cpp:
(WebCore::TextTrack::TextTrack):
(WebCore::TextTrack::setMode):
(WebCore::TextTrack::isRendered):
* html/track/TextTrack.h:
(WebCore::TextTrack::mode):
(TextTrack):

LayoutTests:

Patch by Antoine Quint <graouts@apple.com> on 2013-01-08
Reviewed by Eric Carlson.

* media/track/opera/interfaces/TextTrack/addCue-expected.txt:
* media/track/opera/interfaces/TextTrack/removeCue-expected.txt: Added.
* media/track/opera/interfaces/TextTrackCue/align-expected.txt: Added.
* media/track/opera/interfaces/TextTrackCue/endTime-expected.txt:
* media/track/opera/interfaces/TextTrackCue/id-expected.txt: Added.
* media/track/opera/interfaces/TextTrackCue/pauseOnExit-expected.txt: Added.
* media/track/opera/interfaces/TextTrackCue/startTime-expected.txt:
* media/track/opera/interfaces/TextTrackCue/track-expected.txt: Added.
* platform/chromium/TestExpectations: Skipping newly failing test on Chrome.
* platform/efl/TestExpectations:
* platform/gtk/TestExpectations:
* platform/mac/TestExpectations:
* platform/qt/TestExpectations:
* platform/win/TestExpectations:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@139080 268f45cc-cd09-0410-ab3c-d52691b4dbfc