C77 on 0.68.x test failure

[bsclifton]

Description

When running browser tests, there are two failures

Steps to Reproduce

1. Build Upgrade from Chromium 76.0.3809.132 to Chromium 77.0.3865.75 (uplift to 0.68.x) #5943
2. Run npm run test brave_browser_tests -- Release
3. See two failures

Actual result:

2 tests failed:
    BraveClearDataOnExitTwoBrowsersTest.OneGuest (../../brave/browser/browsing_data/brave_clear_browsing_data_browsertest.cc:335)
    BraveClearDataOnExitTwoBrowsersTest.OneGuestExitsLast (../../brave/browser/browsing_data/brave_clear_browsing_data_browsertest.cc:352)

Expected result:

No failures

Reproduces how often:

100%

[petemill]

As @mkarolin found, pulling in brave/brave-core#2957 fixes this, which was done on 0.69.x with c77 and fixed exactly the same test issues. What 2957 does is removes calls to SetWebUIProperty.

However, 0.68.x NTP is too far away from 0.70.x to easily merge 2957 (which is on 0.70).

0.69 (can easily get 2957 cherry-picked to)

NTP: Added preferences and toggles for Clock / Stats / TopSites
NTP: Move from brave-ui to brave-core
NTP: Make menu keyboard accessible

0.68

NTP: Added preference toggle for background image

Our options are

1. disable those tests in 68 and hope we don't hit the error in real usage
   • Pro: extremely quick
   • Con: Not great to disable tests, and we still don't know why it's an issue. However, it does seem to only be affecting Guest (and possibly Tor) windows.
2. pull in 2957 to 68 and whatever else it needs (most of the 69 list)
   • Pro: fixes the issue
   • Con: bring in more untested features, although a known set affecting the NTP
3. Create a new version of 2957 against 68 that uses current 68 code
   i.e. migrate 0.68 to not use SetWebUIProperty
   • Pro: only changes backend code, not bringing in new features
   • Con: May take a few hours to complete

[bsclifton]

Fixed with #5954