Roll src/third_party/webrtc 9cf6ce3e1bb3..aa3d8ad71b9d (3 commits)

https://webrtc.googlesource.com/src.git/+log/9cf6ce3e1bb3..aa3d8ad71b9d


git log 9cf6ce3e1bb3..aa3d8ad71b9d --date=short --no-merges --format='%ad %ae %s'
2018-12-03 eladalon@webrtc.org Reland "Fix output period in RtcEventLogImpl"
2018-12-03 eladalon@webrtc.org Fix race over RtcEventLogImpl::task_queue_
2018-12-03 henrika@webrtc.org Speculative revert due to a long history of issues related to VP9 on Mac.


Created with:
  gclient setdep -r src/third_party/webrtc@aa3d8ad71b9d

The AutoRoll server is located here: https://autoroll.skia.org/r/webrtc-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:linux_chromium_archive_rel_ng;luci.chromium.try:mac_chromium_archive_rel_ng
TBR=webrtc-chromium-sheriffs-robots@google.com

Change-Id: I2228ae29bbc0df7f026dc5692107cc1b0efb4535
Reviewed-on: https://chromium-review.googlesource.com/c/1358751Reviewed-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@{#613112}

DEPS

@@ -1171,7 +1171,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '5b6cbd789b9b91b4e46dde883c9f2ecb31eddade',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '9cf6ce3e1bb31c96e48016316e4968fd30562d1a',
+    Var('webrtc_git') + '/src.git' + '@' + 'aa3d8ad71b9d1022a94091469e2f457deb7fafc5',
 
   'src/third_party/xdg-utils': {
       'url': Var('chromium_git') + '/chromium/deps/xdg-utils.git' + '@' + 'd80274d5869b17b8c9067a1022e4416ee7ed5e0d',