Roll WebRTC from fce28fa091ae to a0f5e475c56d (2 revisions)

https://webrtc.googlesource.com/src.git/+log/fce28fa091ae..a0f5e475c56d

2020-06-01 landrey@webrtc.org Move kUsedBufferSize to header
2020-06-01 caseyfischer@google.com Revert "Add trace of enqueued and sent RTP packets"

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: I7e3475b7800b872a9d05d71b989ab7b84676436a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225714Reviewed-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@{#773970}

DEPS

@@ -1448,7 +1448,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'fce28fa091ae82feef2e354e934f6c33c31e7ebb',
+    Var('webrtc_git') + '/src.git' + '@' + 'a0f5e475c56d032c4d4b19269e41422afe4a502c',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),