CHROMIUM: Merge remote-tracking branch 'upstream/master' into HEAD

Pull in latest upstream for performance improvements, notably gfxbench
gl_driver2_off.

BUG=b:145579089
TEST=asphalt9, PUBG, gfxbench, various webgl, etc

Change-Id: Ia6bc4973bcd1e9a7b29f27427c2c2c61d10ffaf3