Use gin to add braveSkus handler

[spylogsster]

Resolves brave/brave-browser#20437

• Refactored skus js handler to use gin
• Added overwrite protection
• Added tests
• Made skus origin list configurable by moving it to the browser process and pass via brave_renderer_configuration

Security review https://github.com/brave/security/issues/907

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

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, 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-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

• Try to enable VPN with clean profile

[diracdeltas]

native implementation lgtm, note that it's still overrideable if it's part of window.chrome because window.chrome can be redefined to be anything. is this a problem?

[spylogsster]

native implementation lgtm, note that it's still overrideable if it's part of window.chrome because window.chrome can be redefined to be anything. is this a problem?

chrome exists at the time of call mostly but I wrapped it to be non-writable too

[diracdeltas]

i'm curious what is the output of https://portswigger-labs.net/hackability/inspector/?input=chrome.braveSkus with this PR; cc @thypon
is there a build we can try on M1 macos?

started https://ci.brave.com/job/test-brave-browser-build-macos-arm64/182/

thx, i downloaded this but seems chrome.braveSkus is undefined even after enabling the sku flags in brave://flags/ - is there something else i have to do?

[spylogsster]

thx, i downloaded this but seems chrome.braveSkus is undefined even after enabling the sku flags in brave://flags/ - is there something else i have to do?

Need to enable vpn and 2 skus flags, please pay attention I reworked test via the RenderViewTest and it allowed to keep urls hardcoded inside the renderer process as it was initially. Restarted new build with this changes if required https://ci.brave.com/job/test-brave-browser-build-macos-arm64/183/ cc @diracdeltas @bsclifton

[diracdeltas]

lgtm, what origins do we plan on having chrome.braveSkus available on? only account.brave.com and its staging origins?

[bsclifton]

++ on changes since I last viewed (ex: InitWithFeatures adding SKU to test 😄)