We recently went through updating some libraries hosted on Maven repositories (Google Play Services and Support Library) and we plan to add Dagger soon, which is also hosted on a Maven repository. This is now the case for most libraries in the Android world, as Gradle and Android Studio makes fetching and using them trivial.
That ease of use is not something we get to experience with Chromium’s build system. There are many hurdles: downloading the libraries and their dependencies, writing the GN files, going through open source review, etc. As Dagger’s annotation processor has a lot of dependencies, it's a good opportunity to take time to improve the process, which would impact updating the dependency later, and adding other new dependencies to chrome.
Design doc: go/chromium-m2-repo
Comment 1 by bugdroid1@chromium.org
, Jan 31 2018