This is a space efficient way to store more records about decoded frames,
which is needed for long term references.
Bug: webrtc:9710
Change-Id: I051d59d34a966d48db011142466d9cd15304b7d9
Reviewed-on: https://webrtc-review.googlesource.com/c/116792
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26240}