This fixes a number of things that are warnings in the Mac compiler....

serializer/cross/serializer.cc

 /*
  * Copyright 2009, Google Inc.
  * All rights reserved.
  *
  * 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 279 matching lines @@
     Serialize(writer_, primitive->start_index());
   }
 
   void Visit(Shape* shape) {
     Visit(static_cast<ParamObject*>(shape));
 
     writer_->WritePropertyName("elements");
     writer_->BeginCompacting();
     writer_->OpenArray();
     const ElementRefArray& elements = shape->GetElementRefs();
-    for (int i = 0; i != elements.size(); ++i) {
+    for (ElementRefArray::size_type i = 0; i != elements.size(); ++i) {
       Serialize(writer_, elements[i].Get());
     }
     writer_->CloseArray();
     writer_->EndCompacting();
   }
 
   void Visit(Skin* skin) {
     Visit(static_cast<NamedObject*>(skin));
 
     writer_->WritePropertyName("inverseBindPoseMatrices");
     writer_->BeginCompacting();
     writer_->OpenArray();
     const Skin::MatrixArray& inverse_bind_pose_matrices =
         skin->inverse_bind_pose_matrices();
-    for (int i = 0; i != inverse_bind_pose_matrices.size(); ++i) {
+    for (Skin::MatrixArray::size_type i = 0;
+         i != inverse_bind_pose_matrices.size(); ++i) {
       const Matrix4& matrix = inverse_bind_pose_matrices[i];
       Serialize(writer_, matrix);
     }
     writer_->CloseArray();
     writer_->EndCompacting();
   }
 
   void Visit(Transform* transform) {
     Visit(static_cast<ParamObject*>(transform));
 
     writer_->WritePropertyName("shapes");
     writer_->BeginCompacting();
     writer_->OpenArray();
     const ShapeRefArray& shape_array = transform->GetShapeRefs();
-    for (int i = 0; i != shape_array.size(); ++i) {
+    for (ShapeRefArray::size_type i = 0; i != shape_array.size(); ++i) {
       Serialize(writer_, shape_array[i]);
     }
     writer_->CloseArray();
     writer_->EndCompacting();
 
     writer_->WritePropertyName("parent");
     Serialize(writer_, transform->parent());
   }
 
   StructuredWriter* writer_;
@@ skipping 79 matching lines @@
     WriteObjectBinaryRange(skin);
   }
 
   void Visit(SkinEval* skin_eval) {
     Visit(static_cast<VertexSource*>(skin_eval));
 
     writer_->WritePropertyName("vertexStreams");
     writer_->OpenArray();
     const StreamParamVector& vertex_stream_params =
         skin_eval->vertex_stream_params();
-    for (int i = 0; i != vertex_stream_params.size(); ++i) {
+    for (StreamParamVector::size_type i = 0;
+         i != vertex_stream_params.size(); ++i) {
       const Stream& stream = vertex_stream_params[i]->stream();
       writer_->OpenObject();
       writer_->WritePropertyName("stream");
       Serialize(writer_, stream);
 
       if (vertex_stream_params[i]->input_connection() != NULL) {
         writer_->WritePropertyName("bind");
         Serialize(writer_,
                   GetObjectId(
                       vertex_stream_params[i]->input_connection()->owner()));
       }
 
       writer_->CloseObject();
     }
     writer_->CloseArray();
   }
 
   void Visit(StreamBank* stream_bank) {
     Visit(static_cast<NamedObject*>(stream_bank));
 
     writer_->WritePropertyName("vertexStreams");
     writer_->OpenArray();
     const StreamParamVector& vertex_stream_params =
         stream_bank->vertex_stream_params();
-    for (int i = 0; i != vertex_stream_params.size(); ++i) {
+    for (StreamParamVector::size_type i = 0;
+         i != vertex_stream_params.size(); ++i) {
       const Stream& stream = vertex_stream_params[i]->stream();
       writer_->OpenObject();
       writer_->WritePropertyName("stream");
       Serialize(writer_, stream);
 
       if (vertex_stream_params[i]->input_connection() != NULL) {
         writer_->WritePropertyName("bind");
         Serialize(writer_,
                   GetObjectId(
                       vertex_stream_params[i]->input_connection()->owner()));
@@ skipping 284 matching lines @@
     }
   }
 
 
   writer_->WritePropertyName("objects");
   writer_->OpenObject();
 
   std::vector<const ObjectBase::Class*> classes =
       class_manager_->GetAllClasses();
 
-  for (int i = 0; i != classes.size(); ++i) {
+  for (std::vector<const ObjectBase::Class*>::size_type i = 0;
+       i != classes.size(); ++i) {
     const ObjectBase::Class* current_class = classes[i];
     if (!ObjectBase::ClassIsA(current_class, Param::GetApparentClass())) {
       std::vector<ObjectBase*> objects_of_class;
       for (ObjectBaseArray::const_iterator it = owned_objects.begin();
            it != owned_objects.end(); ++it) {
         if ((*it)->GetClassName() == current_class->name() &&
             !NameStartsWithPrefix(*it, ROOT_PREFIX, NULL)) {
           objects_of_class.push_back(*it);
         }
       }
       if (objects_of_class.size() != 0) {
         writer_->WritePropertyName(current_class->name());
         writer_->OpenArray();
-        for (int j = 0; j != objects_of_class.size(); ++j) {
+        for (std::vector<ObjectBase*>::size_type j = 0;
+             j != objects_of_class.size(); ++j) {
           writer_->OpenObject();
           SerializeObject(objects_of_class[j]);
           writer_->CloseObject();
         }
         writer_->CloseArray();
       }
     }
   }
 
   writer_->CloseObject();
@@ skipping 26 matching lines @@
 
 void Serializer::SerializeSection(ObjectBase* object, Section section) {
   DCHECK(section >= 0 && section < NUM_SECTIONS);
   sections_[section].visitor_->Accept(object);
 }
 
 void Serializer::SerializeParam(Param* param) {
   param_visitor_->Accept(param);
 }
 }  // namespace o3d