GitLab

Track UI and other threads differently in requesting DrawGL. The request
itself is posted through UI thread, so not tracking them separately can
lead to deadlocks. See bug for more detail.

BUG=399745

Review URL: https://codereview.chromium.org/431383003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287713 0039d316-1c4b-4281-b951-d872f2087c98