This could happen because we reset the dirty swap interval flag
before we called makeCurrent.

BUG=angle:481

Change-Id: I5013265b9669ed5055ba8d777d0fcd5588f30b10
Reviewed-on: https://chromium-review.googlesource.com/178582Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Commit-Queue: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Shannon Woods <shannonwoods@chromium.org>
Reviewed-by: Nicolas Capens <nicolascapens@chromium.org>
Commit-Queue: Nicolas Capens <nicolascapens@chromium.org>
Tested-by: Nicolas Capens <nicolascapens@chromium.org>