fixes failing tab transfer test

[bridiver]

https://travis-ci.org/brave/browser-laptop/jobs/239787005#L3218

Strictly speaking this was only a test issue, but I did a small refactoring to make the functionality more consistent and easier to test

Submitter Checklist:

• 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.

Test Plan:

Reviewer Checklist:

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[NejcZdovc]

can you please check if any of tests that are failing now are related to your change

  1) pinnedTabs gets pins from external windows when pinning after creating:
     WaitUntilTimeoutError: Promise was rejected with the following reason: timeout
      at elements(".pinnedTabs [data-test-id="tab"]") - brave.js:428:21

  2) tab tests tab transfer can move into an existing window:
     undefined: Cannot read property 'tabId' of undefined
      at execute(<Function>) - brave.js:526:19

  3) tab tests tab transfer can detach the last tab into an existing window:
     Promise was rejected with the following reason: timeout
  Error

[bridiver]

this fixes #3 and was passing for me locally. I'll check on the others

[NejcZdovc]

In PR you said that this should fix tab tests tab transfer can detach into new windows, but number 3 is tab tests tab transfer can detach the last tab into an existing window it's a different test.

All this 3 tests are failing for me locally.

[bridiver]

yep, read it wrong. I'll check all 3

[bridiver]

looks like a problem with the test themselves, not the code changes. I'll update them

[NejcZdovc]

thank you very much

[bridiver]

the pinned tab test passes for me and the others are updated