Update VDA golden checksum values for EVDA

This CL fixes the checksum values to match that generated by the EVDA after
r235128, which are more correct than before (does not drop last frames).

Also: add support for comments in md5 checksum files for VDA unittest, and use
comments to label golden checksum values by platform.

BUG=321547
TEST=local build, run on CrOS snow

Review URL: https://codereview.chromium.org/82223002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236868 0039d316-1c4b-4281-b951-d872f2087c98
Android: Disable about:flags impl-side-painting override

We don't support running with impl-side painting disabled on Android
anymore. (It's hardcoded to enabled for Android in cc/base/switches.cc)

Removing it from the supported experiments should also cause it to be
ignored at startup when loading the profile (see ConvertFlagsToSwitches called
from ChromeBrowserMainParts::PreCreateThreadsImpl), so that users that turned
this off some time in the past will be forced to enabled again.

BUG=321545
TBR=thakis@chromium.org
NOTRY=True

Review URL: https://codereview.chromium.org/82553012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236869 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236868
SVN changes up to revision 236869