Roll WebRTC from b9fa31958674 to beb741f2ba5d (3 revisions)

https://webrtc.googlesource.com/src.git/+log/b9fa31958674..beb741f2ba5d

2021-04-07 webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com Update WebRTC code version (2021-04-07T04:03:58).
2021-04-06 elrello@microsoft.com Add rollback for send encodings
2021-04-06 etiennep@chromium.org Reland "[Battery]: Delay start of TaskQueuePacedSender." Take 3

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: chromium:1152887,chromium:1188398
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: Ib6a110560ec39e5d1ae361677e6c6004ae445410
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2810620
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#869957}

DEPS

@@ -1553,7 +1553,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/gpuweb/cts.git' + '@' + 'c8e9a0e3d56fb25793de46c02c30b748c167e031',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'b9fa3195867408b8b97a27e9464c583edbf60276',
+    Var('webrtc_git') + '/src.git' + '@' + 'beb741f2ba5d5494f14eec76809702bcbea8d9db',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),