Bump vendoring, move to proto3 release.

recipe_engine/third_party/google/protobuf/reflection.py

 # Protocol Buffers - Google's data interchange format
 # Copyright 2008 Google Inc.  All rights reserved.
 # https://developers.google.com/protocol-buffers/
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 40 matching lines @@
 from google.protobuf.internal import api_implementation
 from google.protobuf import message
 
 
 if api_implementation.Type() == 'cpp':
   from google.protobuf.pyext import cpp_message as message_impl
 else:
   from google.protobuf.internal import python_message as message_impl
 
 # The type of all Message classes.
-# Part of the public interface.
-#
-# Used by generated files, but clients can also use it at runtime:
-#   mydescriptor = pool.FindDescriptor(.....)
-#   class MyProtoClass(Message):
-#     __metaclass__ = GeneratedProtocolMessageType
-#     DESCRIPTOR = mydescriptor
+# Part of the public interface, but normally only used by message factories.
 GeneratedProtocolMessageType = message_impl.GeneratedProtocolMessageType
 
 
 def ParseMessage(descriptor, byte_str):
   """Generate a new Message instance from this Descriptor and a byte string.
 
   Args:
     descriptor: Protobuf Descriptor object
     byte_str: Serialized protocol buffer byte string
 
@@ skipping 33 matching lines @@
     The Message class object described by the descriptor.
   """
   attributes = {}
   for name, nested_type in descriptor.nested_types_by_name.items():
     attributes[name] = MakeClass(nested_type)
 
   attributes[GeneratedProtocolMessageType._DESCRIPTOR_KEY] = descriptor
 
   return GeneratedProtocolMessageType(str(descriptor.name), (message.Message,),
                                       attributes)