Adds initialized to panel and NTP flow

[NejcZdovc]

Resolves brave/brave-browser#11038
Resolves brave/brave-browser#11039
Resolves brave/brave-browser#10783

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).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• 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.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. For instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-compatibility-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

plan 1:

• defined in the issue

plan 2:

• try to combine enabling rewards from all 3 places (NTP, panel and rewards page)

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated.

[tmancey]

LGTM

[emerick]

Elsewhere in our code, I see us calling chrome.send('brave_rewards.saveSetting', [key, enable.toString()]). Might be good to be consistent, unless those are two different use cases?

[NejcZdovc]

yeah tried to do toString, but was failing, will try again

[LaurenWags]

@NejcZdovc and I had a call where we looked at PR build from https://bravesoftware.slack.com/archives/CMH8DU4TF/p1596542545348200

Generally we checked:

• enabling BR from brave://rewards page, panel, and NTP
• after disabling via brave://rewards page, checked re-enabling via same page, panel, and NTP
• checked reset functionality also

We found 3 issues:

1. intermittent race condition with the panel on reset of rewards. sometimes if you reset rewards and the panel is busy it doesn't save state properly and so instead of getting the initial panel you get the "welcome back" panel.
2. issue with NTP widget if you're working within the same window. example: disable or reset rewards. Open a new tab and try to join back from NTP widget. It doesn't work. however, if you have two windows open and you disable/reset rewards in one and then switch to the second window and attempt to join back from NTP widget in second window, this works as expected.
3. multiple profile issue logged separately with [Desktop] disabling Rewards for one profile when other profile(s) are running Rewards causes problem brave-browser#11074

@NejcZdovc if I missed anything please feel free to add 😄

[emerick]

LGTM

[NejcZdovc]

CI failed on unrelated browser test

[LaurenWags]

Verified using

Brave | 1.14.18 Chromium: 84.0.4147.105 (Official Build) nightly (64-bit)
-- | --
Revision | a6b12dfad6663f13a7e16e9a42a6a4975374096b-refs/branch-heads/4147@{#943}
OS | macOS Version 10.14.6 (Build 18G3020)

For brave/brave-browser#11038:

• Verified STR from [Desktop] re-enabling Rewards from panel doesn't work brave-browser#11038 (comment). Confirmed able to rejoin Rewards from panel, services started as expected, brave://rewards page showed rewards enabled correctly, no error in terminal
• Verified STR from [Desktop] re-enabling Rewards from panel doesn't work brave-browser#11038 (comment). Confirmed able to toggle rewards off/on from brave://rewards page both before and after rejoining via panel.
• Verified STR from [Desktop] re-enabling Rewards from panel doesn't work brave-browser#11038 (comment). Note, the welcome message may flash briefly but panel does update to correct pre-opt-in state.

For brave/brave-browser#11039:

• Verified STR from [Desktop] re-enabling Rewards from NTP widget doesn't update display of widget brave-browser#11039 (comment). Confirmed able to rejoin rewards from NTP widget, services started as expected, brave://rewards page showed rewards enabled correctly.

Since brave/brave-browser#10783 is labeled QA/No, no specific checks were completed for this.

Additionally did the following checks:

• Generally confirmed I was able to turn on Rewards from brave://rewards, panel, NTP widget
• Generally confirmed after turning off Rewards via brave://rewards page, I could re-enable via brave://rewards, panel, NTP
• Generally confirmed after reset of Rewards I could re-join via brave://rewards, panel, NTP widget