Track the number of samples that are decoded until a fallback to software decoder happens. Bug: chromium:1061376 Change-Id: Ida3ae94034ec83a6d28001cb7be343b8b99b99c3 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/170468 Commit-Queue: Johannes Kron <kron@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30814}