This flag wasn't being set in the 2D version of this method. The bug
would only cause a performance penalty on Windows XP machines.

BUG=angle:729

Change-Id: I516206740becc90438d613ae9abb3ac550733aed
Reviewed-on: https://chromium-review.googlesource.com/219860Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>