Comment by Etheryte

For context, I once found a bug in Chromium and fixed it, the initial build took a few days on and off on my development laptop that was pretty beefy for the time. I say on and off because I had to interrupt the build if I wanted to do anything else computationally taxing. They have incremental builds and caches all properly set up so you can just continue where you left off after the fact. After the initial build it's pretty fast, 5 minutes or so per build for me. On a low end device you're easily looking at a build time of a week or more if you're starting from scratch.