I've consolidated most of the changes in chrome/browser/abp and used shim's for the other modifications so rebase is light and handleable by Claude. I'd love to get this upstreamed. An intro to the chromium maintenance team would be greatly appreciated!
Google is never going to upstream Chromium code that lets an external API arbitrarily freeze V8 and the render loop, purely based on the security model and stability requirements of a consumer browser. Your only real path forward is maintaining a custom patchset on top of stable releases, exactly like Brave or Electron do. Just be prepared that Claude won't save you when they inevitably rewrite the Blink architecture again
It's a long shot but getting ABP to be a first party citizen alongside CDP would be my dream!