Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/python/google/protobuf/pyext/map_container.h

Index: third_party/protobuf/python/google/protobuf/pyext/map_container.h
diff --git a/third_party/protobuf/python/google/protobuf/pyext/map_container.h b/third_party/protobuf/python/google/protobuf/pyext/map_container.h
index 2de611875dab31191f1af7573e0d73d06549090c..fbd6713f7319da73e7c45e79c7940f00bb89526c 100644
--- a/third_party/protobuf/python/google/protobuf/pyext/map_container.h
+++ b/third_party/protobuf/python/google/protobuf/pyext/map_container.h
@@ -55,6 +55,7 @@ using internal::shared_ptr;
 namespace python {
 
 struct CMessage;
+struct CMessageClass;
 
 // This struct is used directly for ScalarMap, and is the base class of
 // MessageMapContainer, which is used for MessageMap.
@@ -104,15 +105,23 @@ struct MapContainer {
 };
 
 struct MessageMapContainer : public MapContainer {
-  // A callable that is used to create new child messages.
-  PyObject* subclass_init;
+  // The type used to create new child messages.
+  CMessageClass* message_class;
 
   // A dict mapping Message* -> CMessage.
   PyObject* message_dict;
 };
 
-extern PyTypeObject ScalarMapContainer_Type;
-extern PyTypeObject MessageMapContainer_Type;
+#if PY_MAJOR_VERSION >= 3
+  extern PyObject *MessageMapContainer_Type;
+  extern PyType_Spec MessageMapContainer_Type_spec;
+  extern PyObject *ScalarMapContainer_Type;
+  extern PyType_Spec ScalarMapContainer_Type_spec;
+#else
+  extern PyTypeObject MessageMapContainer_Type;
+  extern PyTypeObject ScalarMapContainer_Type;
+#endif
+
 extern PyTypeObject MapIterator_Type;  // Both map types use the same iterator.
 
 // Builds a MapContainer object, from a parent message and a
@@ -124,7 +133,7 @@ extern PyObject* NewScalarMapContainer(
 // field descriptor.
 extern PyObject* NewMessageMapContainer(
     CMessage* parent, const FieldDescriptor* parent_field_descriptor,
-    PyObject* concrete_class);
+    CMessageClass* message_class);
 
 }  // namespace python
 }  // namespace protobuf