It's used here:

https://github.com/google/google-api-java-client/blob/57fe35766cbba0a0d5a9a296be81468d730a29f8/google-api-client-android/src/main/java/com/google/api/client/googleapis/extensions/android/gms/auth/GoogleAccountCredential.java#L294

The method is deprecated due to requiring MANAGE_ACCOUNTS and USE_CREDENTIALS permissions:

https://developers.google.com/android/reference/com/google/android/gms/auth/GoogleAuthUtil#invalidateToken(android.content.Context, java.lang.String)

The replacement is GoogleAuthUtil.clearToken. This should allow Android developers to use the library without requesting those extra permissions.