cosmetic blocking flag causes shields ad toggle to not work correctly

[LaurenWags]

Description

If you enable the cosmetic blocking flag (you must do this manually on 1.5.x, but it is enabled by default on 1.7.x), and you change the cross site trackers toggle to OFF, ads do not start appearing on web pages as expected. You must toggle shields off entirely.

Note - if you disable cosmetic blocking flag, this is not an issue, the Cross-site trackers toggle works as expected.

Steps to Reproduce

1. If using 1.5.x, enable the brave://flags/#brave-adblock-cosmetic-filtering flag. If using 1.7.x it should be enabled by default.
2. Navigate to a site like slashdot.org --> ads not displayed as expected.

3. Open shields, toggle off Cross-site trackers blocked.
   --> ads are not displayed on the page

4. Toggle shields off entirely.
   --> now ads are displayed on the page

If you disable the brave://flags/#brave-adblock-cosmetic-filtering, then the Cross-site trackers blocked toggle begins working as expected (after browser restart.

Actual result:

When cosmetic blocking flag is enabled and you toggle Cross-site trackers blocked OFF, sites do not show ads as expected

Expected result:

Toggling Cross site trackers blocked to OFF should show ads regardless of the cosmetic blocking flag setting:

Reproduces how often:

easily

Brave version (brave://version info)

Brave	1.5.111 Chromium: 80.0.3987.132 (Official Build) (64-bit)
Revision	fcea73228632975e052eb90fcf6cd1752d3b42b4-refs/branch-heads/3987@{#974}
OS	macOS Version 10.14.6 (Build 18G3020)

Brave	1.7.58 Chromium: 80.0.3987.132 (Official Build) dev (64-bit)
Revision	fcea73228632975e052eb90fcf6cd1752d3b42b4-refs/branch-heads/3987@{#974}
OS	macOS Version 10.14.6 (Build 18G3020)

Version/Channel Information:

• Can you reproduce this issue with the current release? 1.4.x n/a, but yes to 1.5.x
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the dev channel? yes
• Can you reproduce this issue with the nightly channel? unsure but probably

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? disabling shields entirely is the solution
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

reproduces on other sites like buzzfeed.com, etc.

[LaurenWags]

for comparison, here's how the same site behaves when cosmetic blocking flag is Disabled on brave://flags

Default shields:

Only Cross-site trackers blocked toggled off:

Shields off entirely:

[LaurenWags]

cc @rebron @kjozwiak @bsclifton as this will be an issue in 1.5.x, but the flag must be enabled manually on 1.5.x. we should fix this for 1.7.x release though.

[pes10k]

@LaurenWags is the expected behavior here to tie cosmetic filtering to the Cross-site trackers toggle? If so, i'd vote against that, since there is (in almost all cases) no connection between the cosmetic filtering and tracking.

Would either of the following solutions work?

1. keeping the flag for cosmetic filtering, enabled by default, but which people can turn off globally if they really don't want it
2. add a shields toggle for cosmetic filtering

FWIW, i have a weak pref against putting cosmetic filtering in shields, since the shield metaphor suggests privacy-protections

[LaurenWags]

@pes10k those are probably better aimed at product for a preferred solution 😄 I was just confused when I toggled cross-site trackers (the "ad" toggle) and ads didn't display - until I tracked it down to the cosmetic blocking flag.

@rebron could you take a look @pes10k suggestions?

[ryanbr]

Having a separate shields switch for cosmetic filtering would be helpful for debugging purposes if there an issue with a cosmetic filter we could track down more quickly

[pes10k]

I've got no beef with another toggle, its just a matter of slotting it in w/ the other priorities. I know @tomlowenthal is also pushing for more shield configurability. @ryanbr could you create an issue for it, if it doesn't exist here, and we can triage and work through it from there?

[rebron]

cc: @antonok-edm