Roll src/third_party/webrtc 63288e382aeb..e77912ba8c0f (2 commits)

https://webrtc.googlesource.com/src.git/+log/63288e382aeb..e77912ba8c0f

git log 63288e382aeb..e77912ba8c0f --date=short --first-parent --format='%ad %ae %s'
2020-02-28 marinaciocea@webrtc.org Insert frame transformer between Encoded and Packetizer.
2020-02-28 kwiberg@webrtc.org Test copying of variable-sized ArrayView rvalues

Created with:
  gclient setdep -r src/third_party/webrtc@e77912ba8c0f

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: None
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: I0a073c2928926df421e1aa35147c8cd7eb619f21
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2080050Reviewed-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@{#745413}

DEPS

@@ -1431,7 +1431,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/gpuweb/cts.git' + '@' + 'ec18cc3262922e7dcdbe70243c6f40606f979144',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '63288e382aebd34b668ae3522ed44df59432c797',
+    Var('webrtc_git') + '/src.git' + '@' + 'e77912ba8c0f0a768dc79ea33d72707aad04b972',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),