Add support for ABP filter redirects as mock responses

[bbondy]

Fix: brave/brave-browser#6894

Unlike extensions like uBlock, we don't do this via data: URLs.
This means that the response will appear to a website as a 200 with the proper mime type, but with the content we want from the resources JSON file.

See also:
brave/internal#660
brave/adblock-rust#29
brave/adblock-rust#50
brave/adblock-rust-ffi#8
brave/brave-core-crx-packager#74

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
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• 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-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
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

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.

[emerick]

LGTM, just mentioned a couple of nits.

[pes10k]

This results in less code i wrote shipping in brave-core, so thats an automatic good thing for product ;)

More seriously, terrific and fantastic :)

[iefremov]

LGTM in general, mostly readability and style-related comments

[fmarier]

Not sure whether this is the right PR for this comment, but as far as I can see from https://github.com/brave/brave-core-crx-packager/pull/74/files#diff-90ea3bb8e019a7c1cb21f2332bf78c75R13, we appear to be pulling the scriptlets directly from the uBlock origin repo.

In the security review, @diracdeltas and I manually reviewed all existing scriptlets and then asked for a Brave clone of that repo so that we could review any new ones as they get added.

[antonok-edm]

@fmarier that directory submodules/uBlock is a git submodule pulled from the Brave fork, not the upstream uBlock repo.

It looks like the URL of the uBlock git archive did end up sneaking through into that PR, but it's not used anywhere and I just filed brave/brave-core-crx-packager#75 to remove it.

[fmarier]

Thanks for the clarifications @antonok-edm.