GitLab

The surface builds up a list of overlays as they come in and HDC
is modified to do the page flip + present all overlays in one go.

BUG=380861
NOTRY=true

Review URL: https://codereview.chromium.org/371813004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282662 0039d316-1c4b-4281-b951-d872f2087c98