Roll src/third_party/webrtc 93d4c10ffccc..e21f3f574b59 (4 commits)

https://webrtc.googlesource.com/src.git/+log/93d4c10ffccc..e21f3f574b59

git log 93d4c10ffccc..e21f3f574b59 --date=short --no-merges --format='%ad %ae %s'
2019-08-20 nisse@webrtc.org Revert "Delete mac_utils.h and mac_utils.cc"
2019-08-20 tommi@webrtc.org Make the callbacks to PollStats for RampUp* tests more regular.
2019-08-20 nisse@webrtc.org Delete mac_utils.h and mac_utils.cc
2019-08-20 peah@webrtc.org Removing all external access to the integer sample data in AudioBuffer

Created with:
  gclient setdep -r src/third_party/webrtc@e21f3f574b59

The AutoRoll server is located here: https://autoroll.skia.org/r/webrtc-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


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

Bug: chromium:None,chromium:993688,chromium:None
Change-Id: I66d7b5127df296ab6cfa68fbd6d246e88ddfb178
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761831Reviewed-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@{#688491}

DEPS

@@ -1391,7 +1391,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'abaae129d9a0c6e1e092067e0b105475df43352e',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '93d4c10ffccc2faf2e38bab74ba14414751bae91',
+    Var('webrtc_git') + '/src.git' + '@' + 'e21f3f574b59cf0517414cd8c655f7629ab80607',
 
   'src/third_party/xdg-utils': {
       'url': Var('chromium_git') + '/chromium/deps/xdg-utils.git' + '@' + 'd80274d5869b17b8c9067a1022e4416ee7ed5e0d',