RFR: 8301022: Video distortion is observed while playing youtube video [v2]

[Jay Bhaskar]

> Issue: current update is breaking the rendering of media controls on youtube video playback
>            For the Webkit Gtk platform, the layout class name is returned as AdwaitaLayoutTraits
>            which is incompatible with the JAVA platform.
> Solution: Use mediaControlsAdwaitaJavaScript and mediaControlsAdwaitaUserAgentStyleSheet
>                 which is compatible with RenderThemeJava. 
> Test: After the fix, open youtube.com and play any video, mouse hover on the video area, control should come up.
>          Without the fix, open youtube.com and play any video, mouse hover on the video area, and the control 
>           should come up overlapping with each other.

Jay Bhaskar has updated the pull request incrementally with one additional commit since the last revision:

  clean up , #if PLATFORM(JAVA) not valid

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1045/files
  - new: https://git.openjdk.org/jfx/pull/1045/files/a26dd884..d7fef32c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1045&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1045&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1045.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1045/head:pull/1045

PR: https://git.openjdk.org/jfx/pull/1045