Roll DevTools Frontend from fea01bf21b37 to 721ef456ee27 (1 revision)

https://chromium.googlesource.com/devtools/devtools-frontend.git/+log/fea01bf21b37..721ef456ee27

2020-12-11 sigurds@chromium.org Refactor ApplicationPanelTreeElement

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/devtools-frontend-chromium
Please CC devtools-waterfall-sheriff-onduty@grotations.appspotmail.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/+doc/master/autoroll/README.md

Bug: chromium:1157484
Tbr: devtools-waterfall-sheriff-onduty@grotations.appspotmail.com
Change-Id: Ie332f48ad59eace2343ac01578e7960fc939a532
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2586752Reviewed-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@{#836056}

DEPS

@@ -274,7 +274,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling devtools-frontend
   # and whatever else without interference from each other.
-  'devtools_frontend_revision': 'fea01bf21b37ff461eec509281b29d9d281ba7b3',
+  'devtools_frontend_revision': '721ef456ee274ae30e8b506a140beb6fd977ba51',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling libprotobuf-mutator
   # and whatever else without interference from each other.