Roll WebRTC from b774d38d3143 to 4c87d83d0323 (2 revisions)

https://webrtc.googlesource.com/src.git/+log/b774d38d3143..4c87d83d0323

2020-09-21 ilnik@webrtc.org Extend I420 frame buffer pool to also create NV12 buffers
2020-09-21 asapersson@webrtc.org Add support so requested resolution alignment also apply to scaled layers.

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: Ic7c55e60be09650d82fa34fb26051a81ff1c6cd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2421538Reviewed-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@{#808859}

DEPS

@@ -1476,7 +1476,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'b774d38d31434e2c09dbab2b1218bfcd221919d2',
+    Var('webrtc_git') + '/src.git' + '@' + '4c87d83d03233a7dff6d71b87eaaa2b683adf632',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),