Roll WebRTC from 4b860c1fb389 to 704fb55255c8 (2 revisions)

https://webrtc.googlesource.com/src.git/+log/4b860c1fb389..704fb55255c8

2020-05-20 danilchap@webrtc.org In common_audio/ and modules/audio_* replace mock macros with unified MOCK_METHOD macro
2020-05-20 sprang@webrtc.org Reland "Removes lock release in PacedSender callback."

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: Id71b29c555b46640638da42b0b11be6f00e95b99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210383Reviewed-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@{#770626}

DEPS

@@ -1453,7 +1453,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '4b860c1fb389b641acf8595a1ca38fd07f11bc2d',
+    Var('webrtc_git') + '/src.git' + '@' + '704fb55255c85cc3b36d91df3209d153bb2f9c02',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),