Turning the threaded compositor into a runtime option. This CL
must land after https://bugs.webkit.org/show_bug.cgi?id=69391

BUG=none
TEST=Covered by existing compositor tests
Review URL: http://codereview.chromium.org/8139020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@104542 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed