Roll WebRTC from b70c9531ee0c to 54b925cfc2cd (6 revisions)

https://webrtc.googlesource.com/src.git/+log/b70c9531ee0c..54b925cfc2cd

2021-01-28 philipp.hancke@googlemail.com add metrics for bundle usage
2021-01-28 perkj@webrtc.org Ensure VideoLayersAllocation.frame_rate_fps can not overflow
2021-01-28 danilchap@webrtc.org Avoid treating VP8 key frame in simulcast as delta frame
2021-01-28 chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com Roll chromium_revision 84c1288826..ba13ceb157 (847739:848044)
2021-01-28 mbonadei@webrtc.org Move some RTC_LOG to RTC_DLOG.
2021-01-28 glahiru@webrtc.org Remove DtlsHandShakeError and replace it with a Function Pointer.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/webrtc-chromium-autoroll
Please CC webrtc-chromium-sheriffs-robots@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md

Bug: None
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: Ia65b09e801845f4454e5e83e2efd5bbcfcb4a3ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2657040
Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#848229}