Add labels to media test pages that play 4K and/or 50FPS content.
Create 2 benchmarks for ChromeOS devices, one playing only 4-content, the other playing all other test content.

BUG=339837

Review URL: https://codereview.chromium.org/134243003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248876 0039d316-1c4b-4281-b951-d872f2087c98
Parse blink platform log channel command line args in webkit unit tests.

This should make debugging webkit unit tests a bit easier.

R=jochen@chromium.org,japhet@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/139783014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248877 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248877