Roll src/third_party/webrtc 47cd4085b978..52e2dbf1c115 (4 commits)

https://webrtc.googlesource.com/src.git/+log/47cd4085b978..52e2dbf1c115

git log 47cd4085b978..52e2dbf1c115 --date=short --first-parent --format='%ad %ae %s'
2020-04-03 mbonadei@webrtc.org Add voip_unittests to gn_isolate_map.pyl
2020-04-03 jonaso@webrtc.org Don't trigger OnNetworkChange when changing from 3G to 4G
2020-04-03 jonaso@webrtc.org Add new AdapterTypes to android sdk
2020-04-03 deadbeef@webrtc.org Temporarily increase DTLS buffer size to 2.

Created with:
  gclient setdep -r src/third_party/webrtc@52e2dbf1c115

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:1063834
Tbr: webrtc-chromium-sheriffs-robots@google.com
Change-Id: I6b31577b50d696823ed779dd6613cf98dc78c43c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135601Reviewed-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@{#756245}

DEPS

@@ -1458,7 +1458,7 @@ deps = {
   },
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '47cd4085b978d14022be068fed518e691cc246ef',
+    Var('webrtc_git') + '/src.git' + '@' + '52e2dbf1c11578414ffb5b155bf97a84b6ad647f',
 
   'src/third_party/libgifcodec':
      Var('skia_git') + '/libgifcodec' + '@'+  Var('libgifcodec_revision'),