Mark video tests for rebaseline now that composited video is on.

TBR=scherkus
BUG=365857

Review URL: https://codereview.chromium.org/445053002

git-svn-id: svn://svn.chromium.org/blink/trunk@179623 bbb929c8-8fbe-4397-9dbb-9b2b20218538