Mojo C++ Bindings: fix mojom::Foo::Deserialize() for component build.

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

 {% for constructor in struct|struct_constructors %}
 {{struct.name}}::{{struct.name}}(
 {%-  for field in constructor.params  %}
 {%-    set type = field.kind|cpp_wrapper_param_type %}
 {%-    set name = field.name %}
     {{type}} {{name}}_in
 {%-    if not loop.last -%},{%- endif %}
 {%-  endfor %})
 {%-  for field, is_parameter in constructor.fields %}
 {%-    set name = field.name %}
@@ skipping 13 matching lines @@
 {%-   for field in struct.fields %}
 {%-     if for_blink %}
   seed = mojo::internal::WTFHash(seed, this->{{field.name}});
 {%-     else %}
   seed = mojo::internal::Hash(seed, this->{{field.name}});
 {%-     endif %}
 {%-   endfor %}
   return seed;
 }
 {%- endif %}
+
+bool {{struct.name}}::Validate(
+    const void* data,
+    mojo::internal::ValidationContext* validation_context) {
+  return Data_::Validate(data, validation_context);
+}