Roll src/third_party/webrtc fb59a6aa3f71..04fd21513bfa (4 commits)

https://webrtc.googlesource.com/src.git/+log/fb59a6aa3f71..04fd21513bfa

git log fb59a6aa3f71..04fd21513bfa --date=short --no-merges --format='%ad %ae %s'
2019-09-20 danilchap@webrtc.org Cleanup passing rtp packet to ulpfec receiver.
2019-09-20 philipel@webrtc.org Removed unused frame_size param from RtpFrameObject ctor.
2019-09-20 nisse@webrtc.org Delete support for enabling adaptive isac mode
2019-09-20 philipel@webrtc.org RtpFrameObject now takes an EncodedImageBuffer in its ctor.

Created with:
  gclient setdep -r src/third_party/webrtc@04fd21513bfa

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

TBR=webrtc-chromium-sheriffs-robots@google.com

Bug: chromium:None
Change-Id: If62c7d4996b16a90b9aa4402e957ca5ad68539a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816817Reviewed-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@{#698498}

DEPS

@@ -1425,7 +1425,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '7c4e67ff117d6c640e6dd17989afe2fb7da7eecb',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'fb59a6aa3f718241506fb644f4daa295f992d596',
+    Var('webrtc_git') + '/src.git' + '@' + '04fd21513bfad682c3e0f5e8c31464b53b4cd0ca',
 
   'src/third_party/xdg-utils': {
       'url': Var('chromium_git') + '/chromium/deps/xdg-utils.git' + '@' + 'd80274d5869b17b8c9067a1022e4416ee7ed5e0d',