Generate LICENSE files in create_dist

[fmarier]

This effectively re-enables the LICENSE file creation and fixes #8618.

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
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Requested a security/privacy review as needed.
• If adding a new directory with NPM packages, ensure this directory is
  added to scripts/audit.js.
• 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-Protection-Mode
  • 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

Test Plan:

1. Go into chrome://credits.
2. Ensure that "Background images" is present and that its licensing info can be expanded.
3. Ensure that "Brave Ad Block" is present and that its licensing info can be expanded.

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions.

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.

[petemill]

@fmarier how long does this step take? Concerned about affecting incremental build time. Perhaps we could just make sure that CI runs it for all PRs? Isn't it already?

[NejcZdovc]

was this just an oversight when merging so CI failed, but was merged anyway? If that is the case I think this step is not needed

[fmarier]

how long does this step take?

On my laptop, it takes 4 ms as measured by:

--- a/lib/build.js
+++ b/lib/build.js
@@ -94,7 +94,10 @@ const build = (buildConfig = config.defaultBuildConfig, options) => {
   touchOverriddenFiles()
   touchOverriddenVectorIconFiles()
   util.updateBranding()
+  const t0 = new Date().getTime();
   licensing.updateLicenses()
+  const t1 = new Date().getTime();
+  console.log('Updating licenses took ' + (t1-t0) + ' ms')

[petemill]

@fmarier lol ok carry on then!

[bridiver]

seems like this should go in create_dist with no guard and then it should run for all PRs and that seems like a more appropriate place for it anyway

[fmarier]

I was aiming to make this fail as early as possible (i.e. anytime a developer builds) so that a simple mistake can't get accidentally get merged to master and break CI builds.

Given the 4 ms overhead, that seems like a reasonable trade-off?

[fmarier]

Changing the approach based on @bridiver 's comments that this would set a bad precedent for other (more expensive) steps to be done in all builds.

Note that this revised PR does not help in any way to protect against mistakes like the one that we saw in brave/brave-core#4398. All it does is move the generation to a different part of the build step so that these checks continue to be done in CI regardless of whether CI does Debug or Release builds.

[fmarier]

In order to re-regenerate the LICENSE files in a local build, now one has to run npm run create_dist.

[bsclifton]

Blocked on resolving #8615