This PR merges the MAS patches into the common/ directory, so they'll be applied unconditionally at patch time, and their functionality toggled at build time. This is because the GN build should not rely on the MAS_BUILD environment variable, but instead only on the GN args system (e.g. so it's possible to have out/Release and out/Release-mas in parallel, without having to coordinate what environment variables are set).
This PR merges the MAS patches into the common/ directory, so they'll be applied unconditionally at patch time, and their functionality toggled at build time. This is because the GN build should not rely on the
MAS_BUILDenvironment variable, but instead only on the GN args system (e.g. so it's possible to haveout/Releaseandout/Release-masin parallel, without having to coordinate what environment variables are set).