Convert a couple of media layouttests to mock scrollbars & rebaseline

Convert a couple of media layouttests to mock scrollbars & rebaseline
https://bugs.webkit.org/show_bug.cgi?id=78634

Unreviewed layouttest rebaselining.

* platform/chromium-gpu-linux/media/video-controls-rendering-expected.png:
* platform/chromium-gpu-linux/media/video-zoom-expected.png:
* platform/chromium-gpu-mac/media/video-controls-rendering-expected.png:
* platform/chromium-gpu-mac/media/video-zoom-expected.png:
* platform/chromium-gpu-win/media/video-controls-rendering-expected.png:
* platform/chromium-gpu-win/media/video-zoom-expected.png:
* platform/chromium-linux/media/video-controls-rendering-expected.png:
* platform/chromium-linux/media/video-zoom-expected.png:
* platform/chromium-mac-leopard/media/video-controls-rendering-expected.png:
* platform/chromium-mac-leopard/media/video-zoom-expected.png:
* platform/chromium-mac-snowleopard/media/video-controls-rendering-expected.png:
* platform/chromium-mac-snowleopard/media/video-zoom-expected.png:
* platform/chromium-win/media/video-controls-rendering-expected.png:
* platform/chromium-win/media/video-zoom-expected.png:
* platform/chromium/test_expectations.txt:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107762 268f45cc-cd09-0410-ab3c-d52691b4dbfc