Roll src/third_party/devtools-frontend/src 075e3e17b781..e784d74686e7 (4 commits)

https://chromium.googlesource.com/devtools/devtools-frontend.git/+log/075e3e17b781..e784d74686e7

git log 075e3e17b781..e784d74686e7 --date=short --first-parent --format='%ad %ae %s'
2020-04-21 tvanderlippe@chromium.org Properly cleanup on process teardown when pre-emptively stopping mocha
2020-04-21 petermarshall@chromium.org [test] Add a test that creates a new Browser window from a BrowserContext
2020-04-21 alexrudenko@chromium.org Make Devices list more accessible
2020-04-21 devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com Update DevTools DEPS.

Created with:
  gclient setdep -r src/third_party/devtools-frontend/src@e784d74686e7

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/+/master/autoroll/README.md

Bug: chromium:1071369
Tbr: devtools-waterfall-sheriff-onduty@grotations.appspotmail.com
Change-Id: Ic8dcdabd578a95315f001d9ab557ad27133e9b6d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2159129Reviewed-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@{#760956}

DEPS

@@ -246,7 +246,7 @@ 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': '075e3e17b7810bb4531822c24bc7984e34d51895',
+  'devtools_frontend_revision': 'e784d74686e7f6fb1f8ef4af3e2eedb37c214a9e',
   # 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.