Roll src/third_party/webrtc 80bc1acb9c2b..dfbfb4606245 (3 commits)

https://webrtc.googlesource.com/src.git/+log/80bc1acb9c2b..dfbfb4606245

git log 80bc1acb9c2b..dfbfb4606245 --date=short --first-parent --format='%ad %ae %s'
2019-12-08 hta@webrtc.org Return an error when datachannel closes due to network error
2019-12-07 titovartem@google.com Migrate WebRTC on FrameGeneratorInterface and remove FrameGenerator class
2019-12-06 trevor.axiom@gmail.com Reland "Reland "Implemented screen enumeration and selection for desktop capture under X11 using the X Resize and Rotate extension version 1.5.""

Created with:
  gclient setdep -r src/third_party/webrtc@dfbfb4606245

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

Bug: chromium:1030631,chromium:396091
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: Ia44fd59a58cf09605d66885dc88f670402762522
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1958167Reviewed-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@{#722920}

DEPS

@@ -1493,7 +1493,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'dd55f3ca8f2ea716ca917a4aaf36f0729fe902b1',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '80bc1acb9c2b9d8096f356c748ec9b57e02759c9',
+    Var('webrtc_git') + '/src.git' + '@' + 'dfbfb46062458cf4a86318e698ce1d1dab145753',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),