Merge "Apilint: No longer flag interface callbacks"

@verifier

def verify_callbacks(clazz):

    """Verify Callback classes.

    All callback classes must be abstract.

    All methods must follow onFoo() naming style."""

    if clazz.fullname == "android.speech.tts.SynthesisCallback": return

        warn(clazz, None, "L1", "Class should be named FooCallback")

    if clazz.name.endswith("Callback"):

        if "interface" in clazz.split:

            error(clazz, None, "CL3", "Callbacks must be abstract class to enable extension in future API levels")

        for m in clazz.methods:

            if not re.match("on[A-Z][a-z]*", m.name):

                error(clazz, m, "L1", "Callback method names must be onFoo() style")