Specifically: ScreenCapturerTest.StartCapture ScreenCapturerTest.Capture WindowCapturerTest.Capture Also adding a DCHECK for the capturer actually being created, since it seems like that's the problem. TBR=zijiehe@chromium.org Bug: webrtc:7830 Change-Id: I200dc0c15f5039b95f591597bc00d3f1084ae876 Reviewed-on: https://webrtc-review.googlesource.com/9562 Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org> Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20297}