This will be used for frame matching in a follow up CL. Bug: webrtc:10365 Change-Id: I57bb743dd10a3327a5befceb98b3539e1138448b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/130510 Commit-Queue: Sebastian Jansson <srte@webrtc.org> Reviewed-by: Magnus Jedvert <magjed@webrtc.org> Cr-Commit-Position: refs/heads/master@{#27398}