Prevent zero-timestamps in captured_frame_.

ViECapturer::OnIncomingCapturedFrame can abort if two frames without a
timestamp are delivered at the same time (the same NTP timestamp is
generated). This currently causes captured_frame_ to be in a state
where timestamps (NTP time etc.) are set, but RTP timestamp is not. This
is an issue if the previous frame in captured_frame_ has yet to be
picked up by the capturer thread, as it will pick up captured_frame_ in
a state where the RTP timestamp has not been set.


Review URL:

Cr-Commit-Position: refs/heads/master@{#9094}
(cherry picked from commit 4a9cb6b67d54c8901ffb0a5d74f9297ac1626fbd)


Review URL:

Cr-Commit-Position: refs/branch-heads/43@{#10}
Cr-Branched-From: 7351f4689caae2e53b3ee54874546e8aab769d22-refs/heads/master@{#8926}
1 file changed