Roll DevTools Frontend from 406249fca52c to 4747e2779d79 (4 revisions)

https://chromium.googlesource.com/devtools/devtools-frontend.git/+log/406249fca52c..4747e2779d79

2020-12-14 jacktfranklin@chromium.org [DataGrid] allow columns to be resized by the mouse
2020-12-14 tvanderlippe@chromium.org [module.json extensions] emulation
2020-12-14 tvanderlippe@chromium.org [module.json extensions] css_overview
2020-12-14 tvanderlippe@chromium.org Add assertNever to platform for exhaustive switch statements

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:1134103,chromium:1153066,chromium:1158395
Tbr: devtools-waterfall-sheriff-onduty@grotations.appspotmail.com
Change-Id: Ib0b35a17a018132f05e71ff31089925e12886b73
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2589662Reviewed-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@{#836673}

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': '406249fca52ca5e1532a9ebe7e97961f7dda0627',
+  'devtools_frontend_revision': '4747e2779d793258e56e9700a454cbec6645a917',
   # 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.