Roll src/third_party/webrtc 3a35312b64a0..2af35ab984e3 (3 commits)

https://webrtc.googlesource.com/src.git/+log/3a35312b64a0..2af35ab984e3

git log 3a35312b64a0..2af35ab984e3 --date=short --first-parent --format='%ad %ae %s'
2020-05-18 handellm@webrtc.org FakeAudioCaptureModule: remove lock recursions.
2020-05-18 marinaciocea@webrtc.org Reland "Make TransformableVideoFrameInterface::GetMetadata pure virtual."
2020-05-18 handellm@webrtc.org VideoAdapter: add missing attribute thread annotations.

Created with:
  gclient setdep -r src/third_party/webrtc@2af35ab984e3

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: chromium:1069295
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: I83c03656d26d898a8cd6d3873baee4f1d885b813
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2207894Reviewed-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@{#769859}

DEPS

@@ -1453,7 +1453,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '3a35312b64a0f272516095d6dce5019181479a22',
+    Var('webrtc_git') + '/src.git' + '@' + '2af35ab984e3d62ff7abb215dc293fc082de19f6',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),