Incoming frames usually have an epoch of time since the capturer was created or similar, not any fixed-time epoch. As such, setting a new capturer resulted in delivering frames with older timestamps which caused these frames to be dropped before encoding. BUG=webrtc:4994 R=stefan@webrtc.org TBR=pthatcher@webrtc.org Review URL: https://codereview.webrtc.org/1345473002 Cr-Commit-Position: refs/heads/master@{#9934}