As of this CL:
https://webrtc-review.googlesource.com/c/src/+/173704
...we now call AudioEncoder::OnReceivedOverhead() too often, since we
don't check if overhead has actually changed.
This CL rectifies that.
Bug: webrtc:10809
Change-Id: I0b86e0296a7860dde3e62e817f9b941fa82afe4a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/175009
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31279}