Roll src/third_party/openscreen/src e998a6b46ddd..56e977406c83 (3 commits)

https://chromium.googlesource.com/openscreen.git/+log/e998a6b46ddd..56e977406c83

git log e998a6b46ddd..56e977406c83 --date=short --first-parent --format='%ad %ae %s'
2020-04-08 jophba@chromium.org Change mixin name from jessie to stretch
2020-04-08 jophba@chromium.org Move from jessie to strech
2020-04-08 jophba@chromium.org Add jessie mixin to arm64_debug trybot

Created with:
  gclient setdep -r src/third_party/openscreen/src@56e977406c83

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/openscreen-chromium
Please CC jophba@chromium.org 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: jophba@chromium.org
Change-Id: I741e3540a16587b8a50c9afce3e0f79fc6078297
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2142207Reviewed-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@{#757575}

DEPS

@@ -1218,7 +1218,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/cisco/openh264' + '@' + '6f26bce0b1c4e8ce0e13332f7c0083788def5fdf',
 
   'src/third_party/openscreen/src':
-    Var('chromium_git') + '/openscreen' + '@' + 'e998a6b46dddfecde30aa25642bad41a7e5d9780',
+    Var('chromium_git') + '/openscreen' + '@' + '56e977406c837e65a188f062b434eb0a81d992f5',
 
   'src/third_party/openxr/src': {
     'url': Var('chromium_git') + '/external/github.com/KhronosGroup/OpenXR-SDK' + '@' + '9e97b73e7dd2bfc07745489d728f6a36665c648f',