Mojo C++ bindings: switch the existing usage of StructTraits to use the new data view interface.

mojo/public/cpp/bindings/lib/array_serialization.h

Index: mojo/public/cpp/bindings/lib/array_serialization.h
diff --git a/mojo/public/cpp/bindings/lib/array_serialization.h b/mojo/public/cpp/bindings/lib/array_serialization.h
index 7cf2945fbf7e2b1db6ebd6a550a21bb3aa3419d7..3b4033b4fdfa47cb6bd14af92f131f041cfb89e6 100644
--- a/mojo/public/cpp/bindings/lib/array_serialization.h
+++ b/mojo/public/cpp/bindings/lib/array_serialization.h
@@ -390,10 +390,9 @@ struct Serializer<Array<Element>, MaybeConstUserType> {
   static bool Deserialize(Data* input,
                           UserType* output,
                           SerializationContext* context) {
-    if (input)
-      return Impl::DeserializeElements(input, output, context);
-    Traits::SetToNull(*output);
-    return true;
+    if (!input)
+      return CallSetToNullIfExists<Traits>(output);
+    return Impl::DeserializeElements(input, output, context);
   }
 };