[EFL] Add inital mediaControlsEflfullscreen.css for fullscreen control UI

[EFL] Add inital mediaControlsEflfullscreen.css for fullscreen control UI
https://bugs.webkit.org/show_bug.cgi?id=86988

Reviewed by Eric Carlson.

In order to support fullscreen feature, EFL port needs to have new css file for fullscreen media control UI.

No new tests because this patch is covered by existing tests.

* PlatformEfl.cmake:
* css/mediaControlsEflFullscreen.css: Added.
(video::-webkit-media-controls-panel):
(video:-webkit-full-page-media::-webkit-media-controls-panel):
(video::-webkit-media-controls-mute-button):
(video::-webkit-media-controls-play-button):
(video::-webkit-media-controls-timeline-container):
(video::-webkit-media-controls-current-time-display):
(video::-webkit-media-controls-time-remaining-display):
(video::-webkit-media-controls-timeline):
(video::-webkit-media-controls-volume-slider-container):
(video::-webkit-media-controls-volume-slider):
(video::-webkit-media-controls-seek-back-button):
(video::-webkit-media-controls-seek-forward-button):
(video::-webkit-media-controls-fullscreen-button):
(video::-webkit-media-controls-rewind-button):
(video::-webkit-media-controls-return-to-realtime-button):
(video::-webkit-media-controls-toggle-closed-captions-button):
* platform/efl/RenderThemeEfl.cpp:
(WebCore):
(WebCore::RenderThemeEfl::extraFullScreenStyleSheet):
* platform/efl/RenderThemeEfl.h:
(RenderThemeEfl):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@117890 268f45cc-cd09-0410-ab3c-d52691b4dbfc