Enable cross-compilation from Linux to Mac

[mherrmann]

The following commands can be used to test the new implementation:

git clone git@github.com:brave/brave-browser.git
cd brave-browser
git clone git@github.com:brave/brave-core.git src/brave

... check out a revision of b-c with the changes from this PR...

npm install
npm config set target_os=mac
npm config set target_arch=x64
npm run init
npm run build -- Static

Resolves https://github.com/brave/devops/issues/7551. Depends on brave/Sparkle#19 and https://github.com/brave/devops/pull/7615.

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:

This change could affect Brave's auto-update functionality on macOS. Please test the scenarios 1.-4. specified under "Test Plan" in #12335. It should be enough to do this on one or two macOS versions, say the most recent one and the oldest one supported by Brave.

[goodov]

What issue we currently have that will be solved by cross-compiling MacOS on Linux? Won't this arise another issues that we will have to deal with? Will Linux be able to compile arm64 binaries?

[simonhong]

With this change, sparkle will be built separatly from b-c?

[mherrmann]

@simonhong yes. See brave/Sparkle#19.

[simonhong]

LGTM for sparkle related changes.

[mherrmann]

We would like to merge this. Even if it doesn't end up getting used in CI, it speeds up builds a little and can help developers (like me) whose primary OS is Linux. @goodov @bridiver can I ask for your review?

[goodov]

can you pls build release builds on this branch (x64 and arm64) to make sure everything's working fine?

[mherrmann]

@goodov sure. There you go:

• x64
• arm64

[goodov]

@goodov sure. There you go:

• x64
• arm64

Thanks. Looks good. Sorry for being too picky, but Release builds don't use Goma. Can you please check that these jobs also work with USE_GOMA disabled?

[mherrmann]

@goodov no problem. Here are the builds without Goma:

• https://ci.brave.com/job/test-brave-browser-build-macos-x64/652/parameters/
• https://ci.brave.com/job/test-brave-browser-build-macos-arm64/180/parameters/

[mherrmann]

@bridiver could you also review or point me to someone else who can unlock this PR?

[mherrmann]

@brave/sec-team we are downloading two new Rust dependencies as part of Brave's build process. There are already several others which we are downloading. Do we need a security review for this?

(This was raised by @bridiver.)

[mherrmann]

Just a quick update that I would merge this but there have been CI problems with Windows and I want a green build before merging. I expect to get it and merge after my PTO next week.