Roll WebRTC from 539e8783de62 to 7a9b96ff8e9f (1 revision)

https://webrtc.googlesource.com/src.git/+log/539e8783de62..7a9b96ff8e9f

2020-07-20 jianj@google.com AV1: set error_resilience to 0.

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: I748fe6d52639ec4e21141dc0b73008bc83f8fd64
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309567Reviewed-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@{#790306}

DEPS

@@ -1476,7 +1476,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '539e8783de6228a56ec3ea5d84ce348082352210',
+    Var('webrtc_git') + '/src.git' + '@' + '7a9b96ff8e9f8d1f5776300e36b7d79797fac7e2',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),