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

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

 // static
 {{struct.name}}Ptr {{struct.name}}::New() {
   {{struct.name}}Ptr rv;
   mojo::internal::StructHelper<{{struct.name}}>::Initialize(&rv);
   return rv;
 }
 
 {{struct.name}}::{{struct.name}}()
 {%- for field in struct.fields %}
     {% if loop.first %}:{% else %} {% endif %} {{field.name}}({{field|default_value}}){% if not loop.last %},{% endif %}
 {%- endfor %} {
 }
 
 {{struct.name}}::~{{struct.name}}() {
 }
 
 {%  if struct|is_cloneable_kind %}
 {{struct.name}}Ptr {{struct.name}}::Clone() const {
   {{struct.name}}Ptr rv(New());
 {%-   for field in struct.fields %}
 {%-     if field.kind|is_object_kind and not field.kind|is_string_kind %}
   rv->{{field.name}} = {{field.name}}.Clone();
 {%-     else %}
   rv->{{field.name}} = {{field.name}};
 {%-     endif %}
 {%-   endfor %}
   return rv;
 }
 {%  endif %}
-
-{{struct.name}}_Reader::{{struct.name}}_Reader(
-    internal::{{struct.name}}_Data*  data,
-    mojo::internal::SerializationContext* context)
-    : data_(data), context_(context) { }
-
-{%- for pf in struct.packed.packed_fields_in_ordinal_order %}
-{%-   set name = pf.field.name -%}
-{%-   set kind = pf.field.kind %}
-{%-   if kind|is_nullable_kind %}
-bool {{struct.name}}_Reader::has_{{name}}() const {
-{%-  if kind|is_union_kind %}
-  return !data_->{{name}}.is_null();
-{%-  elif kind|is_object_kind %}
-  return data_->{{name}}.ptr != nullptr;
-{%-  elif kind|is_interface_kind %}
-  return data_->{{name}}.handle.is_valid();
-{%-  elif kind|is_interface_request_kind %}
-  return data_->{{name}}.is_valid();
-{%-  elif kind|is_associated_interface_kind %}
-  return data_->{{name}}.interface_id == mojo::internal::kInvalidInterfaceId;
-{%-  elif kind|is_associated_interface_request_kind %}
-  return data_->{{name}} == mojo::internal::kInvalidInterfaceId;
-{%-  elif kind|is_any_handle_kind %}
-  return data_->{{name}}.is_valid();
-{%-  else %}
-  return !!data_->{{name}};
-{%-   endif %}
-}
-{%-   endif %}
-{%-   if kind|is_struct_kind and not kind|is_native_only_kind %}
-{{kind|get_name_for_kind}}_Reader {{struct.name}}_Reader::{{name}}() const {
-  return {{kind|get_name_for_kind}}_Reader(data_->{{name}}.ptr, context_);
-}
-{%-   elif kind|is_string_kind %}
-base::StringPiece {{struct.name}}_Reader::{{name}}() const {
-  DCHECK(data_->{{name}}.ptr);
-  return base::StringPiece(data_->{{name}}.ptr->storage(),
-                           data_->{{name}}.ptr->size());
-}
-{%-   endif %}
-{%- endfor %}