Block empty containers

[jonathansampson]

Submitter Checklist:

Resolves #11730

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed. (Ask a Brave employee to help if you cannot access this document.)

Test Plan:

1. Navigate to marketwatch.com
2. Confirm that ads and ad-containers are not shown

Reviewer Checklist:

• Request a security/privacy review as needed if one was not already requested.

[codecov-io]

Codecov Report

Merging #13540 into master will decrease coverage by 0.17%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #13540      +/-   ##
==========================================
- Coverage   56.78%    56.6%   -0.18%     
==========================================
  Files         285      284       -1     
  Lines       29038    28675     -363     
  Branches     4803     4744      -59     
==========================================
- Hits        16488    16231     -257     
+ Misses      12550    12444     -106

Flag	Coverage Δ
#unittest	56.6% <ø> (-0.18%)	⬇️

Impacted Files	Coverage Δ
app/siteHacks.js	48.93% <0%> (-26.83%)	⬇️
js/lib/request.js	28.78% <0%> (-9.1%)	⬇️
app/browser/api/ledger.js	59.67% <0%> (-2.26%)	⬇️
app/common/state/ledgerState.js	84.26% <0%> (-0.69%)	⬇️
app/browser/windows.js	32.99% <0%> (-0.67%)	⬇️
app/cmdLine.js	40% <0%> (-0.57%)	⬇️
js/actions/appActions.js	18.59% <0%> (-0.44%)	⬇️
app/sessionStore.js	88.22% <0%> (-0.19%)	⬇️
app/browser/reducers/tabsReducer.js	40% <0%> (-0.06%)	⬇️
js/constants/appConstants.js	100% <0%> (ø)	⬆️
... and 14 more

[bsclifton]

Works great! 😄 👍

[bsclifton]

master 99c1df9
0.23.x eb8ed69
0.22.x 4200ef6

[mandar-brave]

@bsclifton looks like this regressed; please confirm if OK to re-open

[NejcZdovc]

@mandar-brave this was not shipped yet, it's targeted for single webview release