Roll src/third_party/webrtc 6841d25d45ac..af0aa0977370 (4 commits)

https://webrtc.googlesource.com/src.git/+log/6841d25d45ac..af0aa0977370

git log 6841d25d45ac..af0aa0977370 --date=short --no-merges --format='%ad %ae %s'
2019-10-15 chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com Roll chromium_revision 88a7a882..1c1107d4 (705863:705985)
2019-10-15 danilchap@webrtc.org Replace RtpPacketizerH264::Fragment struct with rtc::ArrayView
2019-10-15 orphis@webrtc.org Update the header extensions capabilities with mid, rid and rrid
2019-10-15 srte@webrtc.org Cleanup: Propagating BitrateAllocationUpdate to RtpVideoSender

Created with:
  gclient setdep -r src/third_party/webrtc@af0aa0977370

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/+/master/autoroll/README.md

TBR=webrtc-chromium-sheriffs-robots@google.com

Bug: chromium:None,chromium:None,chromium:1007894
Change-Id: Icb019d008ff5d03679698e4ff2a5a2a525d2af71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863113Reviewed-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@{#706153}

DEPS

@@ -1470,7 +1470,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '2701c130839edbeb226735b0775966b6423d9e83',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '6841d25d45ac91fb737c3cc5d82240bad0d2740d',
+    Var('webrtc_git') + '/src.git' + '@' + 'af0aa0977370eba9262094b8276ae69b9b7ee600',
 
   'src/third_party/xdg-utils': {
       'url': Var('chromium_git') + '/chromium/deps/xdg-utils.git' + '@' + 'd80274d5869b17b8c9067a1022e4416ee7ed5e0d',