Roll src/third_party/webrtc f4ee036871f2..9427b51d6ff5 (1 commits)

https://webrtc.googlesource.com/src.git/+log/f4ee036871f2..9427b51d6ff5

git log f4ee036871f2..9427b51d6ff5 --date=short --first-parent --format='%ad %ae %s'
2020-04-23 ilnik@webrtc.org Launch external ref control for vp9 encoder

Created with:
  gclient setdep -r src/third_party/webrtc@9427b51d6ff5

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:1027108
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: Ia6e6b541cef86835c907942a04e47c9641c429d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2162647
Reviewed-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@{#761882}

DEPS

@@ -1447,7 +1447,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'f4ee036871f26e350a4f6e242a52fd802c74236d',
+    Var('webrtc_git') + '/src.git' + '@' + '9427b51d6ff50af73c217cb725b1c59b9d701796',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),