modularize-chrome-browser

Modularize a chrome/browser/ subfolder by splitting its sources out of the monolithic //chrome/browser:browser target into dedicated source_set targets in the subfolder's own BUILD.gn. Use when the user asks to modularize, extract, or create BUILD targets for a chrome/browser/ subfolder, or mentions "Project Bedrock", "//chrome/browser modularization", or wants to split a subfolder into header/impl/test targets. Also use when the user says "modularize chrome/browser/X" for any X.