Provide Windows Group Policy templates for Brave

[mherrmann]

In the documentation for Group Policies, we advise administrators to download Chrome's policy_templates.zip and modify it by hand for Brave's registry paths. This PR adds a target for generating our own, branded templates.

Resolves brave/brave-browser#26501. Needs https://github.com/brave/devops/issues/2468 for upload to the web site and GitHub during releases.

Status

It's possible to generate the browser templates when building on Windows via:

npm run build -- --target=brave/components/policy:pack_policy_templates

They get placed in brave_policy_templates.zip.

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:

Download and extract Brave's policy_templates.zip. After https://github.com/brave/devops/issues/2468, this should be available from the web site and the GitHub releases page. Extract it. Open the Windows Group Policy editor. Rightclick Administrative Templates. Select Add/Remove Templates. Click Add and select windows/adm/en-US/brave.adm from the Zip file. After this step, you should see Brave's settings in the Policy Editor. Modify a setting. Open brave://policy and make sure the setting you modified shows up there. You could also perform a functional test that the changed setting really has an effect.

[mherrmann]

Wdyt now @goodov?

[goodov]

looks great, thanks! pls fix few nits and we're good.

[bsclifton]

Not sure how I missed this - but amazing work @mherrmann! 😄 This is something we've wanted for a long time! ❤️

[mherrmann]

Thanks! ☺️