Because they usually happen for all or for no frames in a stream.
Bug: chrome:801327
Change-Id: Ie09b93a0822e821076ff2743cf1223c29fcf44a6
Reviewed-on: https://webrtc-review.googlesource.com/39785
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21644}