Update //third_party/protobuf to version 3.

third_party/protobuf/python/google/protobuf/message.py

 # Protocol Buffers - Google's data interchange format
 # Copyright 2008 Google Inc.  All rights reserved.
-# http://code.google.com/p/protobuf/
+# 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.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
 # in the documentation and/or other materials provided with the
@@ skipping 15 matching lines @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # TODO(robinson): We should just make these methods all "pure-virtual" and move
 # all implementation out, into reflection.py for now.
 
 
 """Contains an abstract base class for protocol messages."""
 
 __author__ = 'robinson@google.com (Will Robinson)'
 
-
 class Error(Exception): pass
 class DecodeError(Error): pass
 class EncodeError(Error): pass
 
 
 class Message(object):
 
   """Abstract base class for protocol messages.
 
   Protocol message classes are almost always generated by the protocol
@@ skipping 120 matching lines @@
       but for messages which are actually groups, this will
       generally be less than len(serialized), since we must
       stop when we reach an END_GROUP tag.  Note that if
       we *do* stop because of an END_GROUP tag, the number
       of bytes returned does not include the bytes
       for the END_GROUP tag information.
     """
     raise NotImplementedError
 
   def ParseFromString(self, serialized):
-    """Like MergeFromString(), except we clear the object first."""
+    """Parse serialized protocol buffer data into this message.
+
+    Like MergeFromString(), except we clear the object first and
+    do not return the value that MergeFromString returns.
+    """
     self.Clear()
     self.MergeFromString(serialized)
 
   def SerializeToString(self):
     """Serializes the protocol message to a binary string.
 
     Returns:
       A binary string representation of the message if all of the required
       fields in the message are set (i.e. the message is initialized).
 
@@ skipping 31 matching lines @@
   # """
   def ListFields(self):
     """Returns a list of (FieldDescriptor, value) tuples for all
     fields in the message which are not empty.  A singular field is non-empty
     if HasField() would return true, and a repeated field is non-empty if
     it contains at least one element.  The fields are ordered by field
     number"""
     raise NotImplementedError
 
   def HasField(self, field_name):
-    """Checks if a certain field is set for the message. Note if the
-    field_name is not defined in the message descriptor, ValueError will be
-    raised."""
+    """Checks if a certain field is set for the message, or if any field inside
+    a oneof group is set.  Note that if the field_name is not defined in the
+    message descriptor, ValueError will be raised."""
     raise NotImplementedError
 
   def ClearField(self, field_name):
+    """Clears the contents of a given field, or the field set inside a oneof
+    group.  If the name neither refers to a defined field or oneof group,
+    ValueError is raised."""
+    raise NotImplementedError
+
+  def WhichOneof(self, oneof_group):
+    """Returns the name of the field that is set inside a oneof group, or
+    None if no field is set.  If no group with the given name exists, ValueError
+    will be raised."""
     raise NotImplementedError
 
   def HasExtension(self, extension_handle):
     raise NotImplementedError
 
   def ClearExtension(self, extension_handle):
     raise NotImplementedError
 
   def ByteSize(self):
     """Returns the serialized size of this message.
@@ skipping 23 matching lines @@
     raise NotImplementedError
 
   def __getstate__(self):
     """Support the pickle protocol."""
     return dict(serialized=self.SerializePartialToString())
 
   def __setstate__(self, state):
     """Support the pickle protocol."""
     self.__init__()
     self.ParseFromString(state['serialized'])