Generate subgroup StyleSurroundData in ComputedStyle.

third_party/WebKit/Source/build/scripts/templates/fields/group.tmpl

+{% from 'fields/field.tmpl' import encode %}
+{% from 'macros.tmpl' import print_if %}
+{% macro def_group(group): -%}

[meade_UTC10, 2017/04/06 03:29:57]

I think this can be named more clearly, group_class_def? class_def_for_group?

[shend, 2017/04/20 03:22:34]

Changed to define_field_group_class.

+class {{group.type_name}} : public RefCounted<{{group.type_name}}> {
+ public:
+  static PassRefPtr<{{group.type_name}}> create() {
+    return adoptRef(new {{group.type_name}});
+  }
+  PassRefPtr<{{group.type_name}}> copy() const {
+    return adoptRef(new {{group.type_name}}(*this));
+  }
+
+  bool operator==(const {{group.type_name}}& o) const {

[meade_UTC10, 2017/04/06 03:29:57]

Not sure if the other generators you've written missed this, but blink style is
to not use abbreviations: https://www.chromium.org/blink/coding-style

o -> other

Now that I think about it, even though tmpl files aren't really C++, we should
probably use that for generator function names too...

[shend, 2017/04/06 04:39:40]

Ah ok, I was merely following the handwritten code here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/style/Sty...

[meade_UTC10, 2017/04/20 03:08:40]

Ah yeah I think some of that is old and predates that style guidance :p

[shend, 2017/04/20 03:22:34]

Changed to 'other'.

+    return (
+    {% for field in group.fields %}
+      {{field.name}} == o.{{field.name}}{{print_if(not loop.last, ' &&')}}
+    {% endfor %}
+    );
+  }
+  bool operator!=(const {{group.type_name}}& o) const { return !(*this == o); }
+
+  {% for field in group.fields %}
+  {% if field.is_bit_field %}

[meade_UTC10, 2017/04/06 03:29:58]

How come some of the if field.is_bit_field is abstracted into field.tmpl, but
this one isn't? Should there be a macro like this:

{% macro define_field_storage(field) %}
{% if field.is_bit_field %}
unsigned {{field.name}} : {{field.size}}; // {{field.type_name}}
{% else %}
{{field.type_name}} {{field.name}};
{% endif %}
{% endmacro %}

then this just becomes

{% for field in group.fields %}
{{define_field_storage(field)}}
{% endfor %}

[shend, 2017/04/20 03:22:34]

Done.

+  unsigned {{field.name}} : {{field.size}}; // {{field.type_name}}
+  {% else %}
+  {{field.type_name}} {{field.name}};
+  {% endif %}
+  {% endfor %}
+
+ private:
+  {{group.type_name}}() :
+  {% for field in group.fields %}
+      {{field.name}}({{encode(field, field.default_value)}}){{print_if(not loop.last, ',')}}
+  {% endfor %}
+  {}
+
+  ALWAYS_INLINE {{group.type_name}}(const {{group.type_name}}& o) :
+      RefCounted<{{group.type_name}}>(),
+  {% for field in group.fields %}
+      {{field.name}}(o.{{field.name}}){{print_if(not loop.last, ',')}}
+  {% endfor %}
+  {}
+};
+{%- endmacro %}