Roll DevTools Frontend from 550dc4dab51d to 1cb771bfe063 (4 revisions)

https://chromium.googlesource.com/devtools/devtools-frontend.git/+log/550dc4dab51d..1cb771bfe063

2020-08-20 alexrudenko@chromium.org Improve adorner test
2020-08-20 sigurds@chromium.org Query the model late for the target
2020-08-20 wolfi@chromium.org Add icon for not reachable top frame to frame tree
2020-08-20 alexrudenko@chromium.org Fix LayoutPane icon appearance in dark mode

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:1093247,chromium:1109177,chromium:1115421
Tbr: devtools-waterfall-sheriff-onduty@grotations.appspotmail.com
Change-Id: I9e93304db6172dd6c76871507b3812feabe121ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2366912Reviewed-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@{#800076}

DEPS

@@ -266,7 +266,7 @@ 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': '550dc4dab51daddb4e04fcd9f66fa48b92cb3074',
+  'devtools_frontend_revision': '1cb771bfe063f93c17d4efbb4615c04716a6aa8f',
   # 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.