DxgiOutputDuplicator AcquireNextFrame timeout can be 0

Timeout of AcquireNextFrame() can be 0. Though MSDN does not state it clear, I
tried it on my laptop, it works well, with almost zero capture time.
The screenshot is at https://drive.google.com/open?id=0B0OFNI4uoZGRNVZxekxCbm0ycmc.

BUG=682112

Review-Url: https://codereview.webrtc.org/2712353002
Cr-Original-Commit-Position: refs/heads/master@{#16953}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 634fcb32e34413da621445722df1a21cb44a32c4
1 file changed