Roll src/third_party/webrtc cc9bf6398c03..2b9317ad76b3 (2 commits)

https://webrtc.googlesource.com/src.git/+log/cc9bf6398c03..2b9317ad76b3

git log cc9bf6398c03..2b9317ad76b3 --date=short --no-merges --format='%ad %ae %s'
2019-11-04 brandtr@webrtc.org Stop checking VP8BaseHeavyTl3RateAllocation field trial on every frame.
2019-11-04 terelius@webrtc.org Return status instead of CHECKing in event log parser.

Created with:
  gclient setdep -r src/third_party/webrtc@2b9317ad76b3

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

TBR=webrtc-chromium-sheriffs-robots@google.com

Bug: chromium:None
Change-Id: Id0d6f1591b0732ecdb99141b93e522b80ff11f22
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1896762Reviewed-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@{#712137}

DEPS

@@ -1512,7 +1512,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'dd55f3ca8f2ea716ca917a4aaf36f0729fe902b1',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'cc9bf6398c0348395442875cec6d14092a1959f7',
+    Var('webrtc_git') + '/src.git' + '@' + '2b9317ad76b3bd3721157c257d93939257088636',
 
   # Wuffs' canonical repository is at github.com/google/wuffs, but we use
   # Skia's mirror of Wuffs, the same as in upstream Skia's DEPS file.