Generate getters/setters for some fields on groups in ComputedStyle

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

Index: third_party/WebKit/Source/build/scripts/templates/fields/external.tmpl
diff --git a/third_party/WebKit/Source/build/scripts/templates/fields/external.tmpl b/third_party/WebKit/Source/build/scripts/templates/fields/external.tmpl
index b5753c26a001eebabd14697eafbff861b33a901b..5e8cf15672dfaf1dd56cabdd69b5b5936582814e 100644
--- a/third_party/WebKit/Source/build/scripts/templates/fields/external.tmpl
+++ b/third_party/WebKit/Source/build/scripts/templates/fields/external.tmpl
@@ -1,8 +1,15 @@
+{% from 'fields/field.tmpl' import decode, encode, getter_expression, setter_expression, return_type %}
 {% import 'fields/base.tmpl' as base %}
 {% from 'fields/field.tmpl' import decode %}
-{% macro decl_methods(field) %}
-{{base.decl_methods(field)}}
+{% macro decl_public_methods(field) %}
+{{base.decl_public_methods(field)}}
 void {{field.setter_method_name}}({{field.type_name}}&& v) {
   {{field.name}} = std::move({{decode(field, "v")}});
 }
 {% endmacro %}
+
+{% macro decl_protected_methods(field) -%}
+{{field.type_name}}& {{field.mutable_method_name}}() {
+  return {{decode(field, getter_expression(field))}};
+}
+{%- endmacro %}