Worked on the denoland/chromium_build repository to introduce a targeted debugging feature for iOS builds by adding a conditional AddressSanitizer (ASAN) toggle. The solution involved creating a new GN build argument that allows ASAN to be enabled on official iOS builds only when explicitly requested, supporting debugging for a specific issue without affecting stable releases. This approach preserved default production behavior while accelerating issue diagnosis on development and beta channels. The work demonstrated skills in build system configuration and debugging, leveraging GN language to implement opt-in sanitization and streamline the debugging process for iOS workflows without introducing regressions.