Mojo C++ bindings: change the first template parameter of StructTraits and UnionTraits.

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

 {%- set mojom_type = union|get_qualified_name_for_kind %}
 {%- set data_type = union|get_qualified_name_for_kind(internal=True) %}
 
 template <>
-struct {{export_attribute}} UnionTraits<{{mojom_type}}, {{mojom_type}}Ptr> {
+struct {{export_attribute}} UnionTraits<{{mojom_type}}::DataView,
+                                        {{mojom_type}}Ptr> {
   static bool IsNull(const {{mojom_type}}Ptr& input) { return !input; }
   static void SetToNull({{mojom_type}}Ptr* output) { output->reset(); }
 
   static {{mojom_type}}::Tag GetTag(const {{mojom_type}}Ptr& input) {
     return input->which();
   }
 
 {%- for field in union.fields %}
 {%-   set return_ref = field.kind|is_object_kind or
                        field.kind|is_any_handle_or_interface_kind %}
 {%-   if return_ref %}
   static decltype(std::declval<{{mojom_type}}>().get_{{field.name}}())
       {{field.name}}({{mojom_type}}Ptr& input) {
     return input->get_{{field.name}}();
   }
 {%-   else %}
   static decltype(std::declval<{{mojom_type}}>().get_{{field.name}}())
       {{field.name}}(const {{mojom_type}}Ptr& input) {
     return input->get_{{field.name}}();
   }
 {%-   endif %}
 {%- endfor %}
 
-  static bool Read({{mojom_type}}DataView input, {{mojom_type}}Ptr* output);
+  static bool Read({{mojom_type}}::DataView input, {{mojom_type}}Ptr* output);
 };
 
 namespace internal {
 
 template <typename MaybeConstUserType>
 struct Serializer<{{mojom_type}}Ptr, MaybeConstUserType> {
   using UserType = typename std::remove_const<MaybeConstUserType>::type;
-  using Traits = UnionTraits<{{mojom_type}}, UserType>;
+  using Traits = UnionTraits<{{mojom_type}}::DataView, UserType>;
 
   static size_t PrepareToSerialize(MaybeConstUserType& input,
                                    bool inlined,
                                    SerializationContext* context) {
     size_t size = inlined ? 0 : sizeof({{data_type}});
 
     if (CallIsNullIfExists<Traits>(input))
       return size;
 
     void* custom_context = CustomContextHelper<Traits>::SetUp(input, context);
@@ skipping 106 matching lines @@
 
     CustomContextHelper<Traits>::TearDown(input, custom_context);
   }
 
   static bool Deserialize({{data_type}}* input,
                           UserType* output,
                           SerializationContext* context) {
     if (!input || input->is_null())
       return CallSetToNullIfExists<Traits>(output);
 
-    {{mojom_type}}DataView data_view(input, context);
+    {{mojom_type}}::DataView data_view(input, context);
     return Traits::Read(data_view, output);
   }
 };
 
 }  // namespace internal