Always having the latest iosurface before invalidating a region. Otherwise if CaptureFrame() happens in between, the capture result may not be fully refreshed. Also we can't add lock since it will impact performance. Bug: webrtc:8652 Change-Id: Ib23105b16065018c691685083b76a771ce8771d3 Reviewed-on: https://webrtc-review.googlesource.com/74643 Reviewed-by: Zijie He <zijiehe@chromium.org> Commit-Queue: Brave Yao <braveyao@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23154}