How to build dynamic (shared) libraries of crashpad?

Crashpad is an error reporting system for c++ apps.https://chromium.googlesource.com/crashpad/crashpad/+/HEAD/doc/developing.md

build instructions are

 $ cd ~/crashpad/crashpad $ gn gen out/Default $ ninja -C out/Default

I can build predefined static libs but I have not found a way how to use gn or ninja to generate the shared libraries.