Require an explicit ServiceName annotation for interfaces in Python.

mojo/public/python/mojo_application/service_provider_impl.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Python implementation of the ServiceProvider interface."""
 
 import logging
 
 import service_provider_mojom
 
 class ServiceProviderImpl(service_provider_mojom.ServiceProvider):
   def __init__(self, provider):
     self._provider = provider
     self._name_to_service_connector = {}
 
-  def AddService(self, service_class):
-    self._name_to_service_connector[service_class.manager.name] = service_class
+  def AddService(self, service_class, service_name=None):
+    if service_name is None:
+      service_name = service_class.manager.service_name
+    if service_name is None:
+      logging.error("No ServiceName specified for %s." % service_class.__name__)
+      return
+    self._name_to_service_connector[service_name] = service_class
 
   def ConnectToService(self, interface_name, pipe):
     if interface_name in self._name_to_service_connector:
       service = self._name_to_service_connector[interface_name]
       service.manager.Bind(service(), pipe)
     else:
       logging.error("Unable to find service " + interface_name)