static String simpleNameOf(String s) {
    if (s.contains(".")) {
      return s.substring(s.lastIndexOf('.') + 1);
    } else {
      return s;
    }
  }
Returns the name of the package that the given type is in. If the type is in the default
(unnamed) package then the name is the empty string.
value/src/main/java/com/google/auto/value/processor/TypeSimplifier.java