https://bugs.webkit.org/show_bug.cgi?id=114230

Reviewed by Jer Noble.

Source/WebCore: 

Test: media/track/track-css-user-override.html

* html/HTMLMediaElement.cpp:
(WebCore::HTMLMediaElement::updateActiveTextTrackCues): Drive by clean-up so we don't log excessively.

* html/shadow/MediaControlElements.cpp:
(WebCore::MediaControlTextTrackContainerElement::MediaControlTextTrackContainerElement): Initialize
    new member variables.
(WebCore::MediaControlTextTrackContainerElement::updateDisplay): Set cue font size when it is
    inserted into the tree.
(WebCore::MediaControlTextTrackContainerElement::updateTimerFired): Update the font size of 
    all active cues.
(WebCore::MediaControlTextTrackContainerElement::updateSizes): Set size-relative CSS properties
    after a time because this can be called during layout.
* html/shadow/MediaControlElements.h:

* html/shadow/MediaControls.cpp:
(WebCore::MediaControls::textTrackPreferencesChanged): Call clos...