Mojo C++ bindings: Generate InterfaceHandle<> instead of InterfacePtr<>.

mojo/public/tools/bindings/generators/cpp_templates/union_serialization_definition.tmpl

 {% import 'struct_macros.tmpl' as struct_macros without context %} 
 size_t GetSerializedSize_(const {{union.name}}Ptr& input, bool inlined) {
   size_t size = 0U;
   if (!inlined) {
     size += sizeof(internal::{{union.name}}_Data);
   }
 
   if (!input)
     return size;
 
@@ skipping 73 matching lines @@
               should_return_errors = true,
               indent_size = 16)|indent(6)}}
 {%-     endif %}
 {%    elif field.kind|is_any_handle_kind %}
         result->data.f_{{field.name}} =
             input_acc.data()->{{field.name}}->release().value();
 {%    elif field.kind|is_interface_kind %}
         mojo::internal::Interface_Data* {{field.name}} =
             reinterpret_cast<mojo::internal::Interface_Data*>(
                 &result->data.f_{{field.name}});
-        mojo::internal::InterfacePointerToData(
+        mojo::internal::InterfaceHandleToData(
             input_acc.data()->{{field.name}}->Pass(), {{field.name}});
 {%    elif field.kind|is_enum_kind %}
         result->data.f_{{field.name}} = 
           static_cast<int32_t>(input_acc.data()->{{field.name}});
 {%    else %}
         result->data.f_{{field.name}} = input_acc.data()->{{field.name}};
 {%-   endif %}
         break;
       }
 {%- endfor %}
@@ skipping 32 matching lines @@
 {%      endif %}
 {%    elif field.kind|is_any_handle_kind %}
         {{field.kind|cpp_wrapper_type}}* {{field.name}} =
             reinterpret_cast<{{field.kind|cpp_wrapper_type}}*>(&input->data.f_{{field.name}});
         output->set_{{field.name}}({{field.name}}->Pass());
 {%    elif field.kind|is_interface_kind %}
         {{field.kind|cpp_wrapper_type}} {{field.name}}_out;
         mojo::internal::Interface_Data* {{field.name}}_in =
             reinterpret_cast<mojo::internal::Interface_Data*>(
                 &input->data.f_{{field.name}});
-        mojo::internal::InterfaceDataToPointer(
+        mojo::internal::InterfaceDataToHandle(
             {{field.name}}_in, &{{field.name}}_out);
         output->set_{{field.name}}({{field.name}}_out.Pass());
 {%    elif field.kind|is_enum_kind %}
         output->set_{{field.name}}(static_cast<{{field.kind|cpp_wrapper_type}}>(input->data.f_{{field.name}}));
 {%    else %}
         output->set_{{field.name}}(input->data.f_{{field.name}});
 {%-   endif %}
         break;
       }
 {%- endfor %}
       default:
         MOJO_LOG(WARNING) << "Deserializing {{union.name}} with unknown tag!";
         // No way to deserialize the data when we encounter an unknown tag.
         break;
     }
   }
 }