Roll WebRTC from aeac9f88598d to ef8507d106ad (5 revisions)

https://webrtc.googlesource.com/src.git/+log/aeac9f88598d..ef8507d106ad

2020-09-11 chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com Roll chromium_revision 55b6d728..86121ae2 (806095:806200)
2020-09-11 kwiberg@webrtc.org Proof of concept: Cancer Stick Castle, a sigslot replacement
2020-09-11 sprang@webrtc.org Updates rtcp::CompoundPacket to contain unique pointers to packets.
2020-09-11 lndmrk@webrtc.org Delete kHEVCCodecName
2020-09-11 jleconte@webrtc.org Change gtest name to allow filtering based on the story name.

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: Ice4ec2b20d6865f978f9ef4606cb4e6b05efed51
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406741Reviewed-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@{#806373}

DEPS

@@ -1471,7 +1471,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'aeac9f88598dcb20693fe52c97f917e43ce0d3c3',
+    Var('webrtc_git') + '/src.git' + '@' + 'ef8507d106ad43009c2b794b99ee9edfa2d85b1f',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),