The extract annotations driver is a command line interface to extracting annotations
from a source tree. It's similar to the gradle
ExtractAnnotations task,
but usable from the command line and outside Gradle, for example
to extract annotations from the Android framework itself (which is not built with
Gradle). It also allows other options only interesting for extracting
platform annotations, such as filtering all APIs and constants through an
API white-list (such that we for example can pull annotations from the master
branch which has the latest metadata, but only expose APIs that are actually in
a released platform), as well as translating android.annotation annotations into
android.support.annotations.