Refactor patch for optimize_webui.py build script to use brave-specific file

[petemill]

There are additions coming to this file to route more webui pages (such as for the chrome://history page). This refactor allows those additions to modify the brave version of this script instead of further modifying the patch to the chromium version of the script.

Fix https://github.com/brave/brave-browser/issues/5233

Submitter Checklist:

• [x] Submitted a ticket for my issue if one did not already exist.
• [x] 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
  • [x] macOS
  • [ ] Windows
• [x] Verified that all lint errors/warnings are resolved (npm run lint)
• [x] Ran git rebase master (if needed).
• [x] Ran git rebase -i to squash commits (if needed).
• [x] Tagged reviewers and labelled the pull request as needed.
• [ ] Request a security/privacy review as needed.
• [x] 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:

• chrome://settings still works and uses brave fonts

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.

[petemill]

@mkarolin thanks for approval - I added an addition to make sure that dependent builds re-build when this new brave-specific file is modified. I'd appreciate a re-review when you get a chance 😄

[rossmoody]

Is there any reason why this PR might make it so you can't clear your history? I built this one working on my little icon side project and I can't seem to get the clear browsing data modal to appear in settings.

Edit: This might help: https://d.pr/i/YH7kSL

[mkarolin]

@rossmoody Clear Browsing Data dialog got broken by the c76 bump. The fix is pending approval here: https://github.com/brave/brave-core/pull/2903/commits/4f8e2b27f553dfad670f2cd42b0653c7f752359a

[bsclifton]

@petemill is this one we still want to do? Or should we close the issue / this PR?

[bsclifton]

Closing as stale