Roll WebRTC from a7e34d33fe70 to 6031b74664d0 (2 revisions)

https://webrtc.googlesource.com/src.git/+log/a7e34d33fe70..6031b74664d0

2021-01-21 ivoc@webrtc.org Implement a Neon optimized function to find the argmax element in an array.
2021-01-21 sprang@webrtc.org Fixes issue triggered by WebRTC-VP9-PerformanceFlags trial.

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: chromium:1167353,chromium:12355
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: I1db0278740ff3e8346c4dc293edd633f6efd2982
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2643136Reviewed-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@{#845724}

DEPS

@@ -1515,7 +1515,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/gpuweb/cts.git' + '@' + '3c2fe3888658d82b47ca831d59a2e07579619c2d',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'a7e34d33fe70363acdabd41fe14f91469cdc1619',
+    Var('webrtc_git') + '/src.git' + '@' + '6031b74664d0be40d7f913600d17f6d8d1323729',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),