b56cca3282
This change removes the old `ContributingSources` class. It has been replaced by the new `SourceTracker`. Bug: webrtc:10793 Change-Id: Ibd481cf6584837c46b229b9fc2a071362f07d361 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/147878 Reviewed-by: Erik Språng <sprang@webrtc.org> Commit-Queue: Chen Xing <chxg@google.com> Cr-Commit-Position: refs/heads/master@{#28756}