Roll src/third_party/webrtc b63331bb8f7f..3b6afeeed0a9 (3 commits)

https://webrtc.googlesource.com/src.git/+log/b63331bb8f7f..3b6afeeed0a9

git log b63331bb8f7f..3b6afeeed0a9 --date=short --first-parent --format='%ad %ae %s'
2020-05-07 eshr@google.com Add comparison methods for VideoSourceRestrictions
2020-05-07 eshr@google.com [Adaptation] Adapt up requires previous underuse
2020-05-07 saza@webrtc.org Remove audio playout generator from APM API

Created with:
  gclient setdep -r src/third_party/webrtc@3b6afeeed0a9

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

Bug: None
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: I4d3cc2ee0bab8c34b29036dc839d7075f31dbc1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2187897Reviewed-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@{#766449}

DEPS

@@ -1453,7 +1453,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'b63331bb8f7fc21ceb2d3dabfd977e535559ff23',
+    Var('webrtc_git') + '/src.git' + '@' + '3b6afeeed0a9115660f279066447f62e512c56c4',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),