Make ComputedStyleBase abstract.

third_party/WebKit/Source/build/scripts/templates/ComputedStyleBase.h.tmpl

 {% from 'macros.tmpl' import license, print_if %}
 {{license()}}
 
 #ifndef ComputedStyleBase_h
 #define ComputedStyleBase_h
 
 #include "core/ComputedStyleBaseConstants.h"
 #include "core/CoreExport.h"
 {% for path in include_paths %}
 #include "{{path}}"
 {% endfor %}
 
 {# Each field template has macros that we can call to generate specific
    aspects of the field (e.g. getters, setters).
 #}
 {% import 'fields/keyword.tmpl' as keyword %}
 {% import 'fields/flag.tmpl' as flag %}
 {% import 'fields/monotonic_flag.tmpl' as monotonic_flag %}
 {% set field_templates = { 'keyword': keyword, 'flag': flag, 'monotonic_flag': monotonic_flag } %}
 
 namespace blink {
 
 // The generated portion of ComputedStyle. For more info, see the header comment
 // in ComputedStyle.h.
 class CORE_EXPORT ComputedStyleBase {
  public:
-  ALWAYS_INLINE ComputedStyleBase() :
-  {% for field in fields %}
-      {{field.name}}(static_cast<unsigned>({{field.default_value}})){{print_if(not loop.last, ',')}}
-  {% endfor %}
-  {}
-  ~ComputedStyleBase() {}
-
-  ALWAYS_INLINE ComputedStyleBase(const ComputedStyleBase& o) :
-  {% for field in fields %}
-      {{field.name}}(o.{{field.name}}){{print_if(not loop.last, ',')}}
-  {% endfor %}
-  {}
-
   inline bool independentInheritedEqual(const ComputedStyleBase& o) const {
     return (
     {% for field in fields if field.is_property and field.is_inherited and field.is_independent %}
         {{field.name}} == o.{{field.name}}{{print_if(not loop.last, ' &&')}}
     {% endfor %}
     );
   }
 
   inline bool nonIndependentInheritedEqual(const ComputedStyleBase& o) const {
     return (
@@ skipping 32 matching lines @@
   // Fields.
   // TODO(sashab): Remove initialFoo() static methods and update callers to
   // use resetFoo(), which can be more efficient.
 
   {% for field in fields %}
   // {{field.property_name}}
   {{field_templates[field.field_template].decl_methods(field)|indent(2)}}
 
   {% endfor %}
  protected:
+  ALWAYS_INLINE ComputedStyleBase() :
+  {% for field in fields %}
+      {{field.name}}(static_cast<unsigned>({{field.default_value}})){{print_if(not loop.last, ',')}}
+  {% endfor %}
+  {}
+
+  ~ComputedStyleBase() = default;

[sashab, 2017/03/16 23:55:31]

I like this, but can we add a comment here like:
// Make the ComputedStyleBase destructor protected so that you can only create
one if it is a ComputedStyle.

+
+  ALWAYS_INLINE ComputedStyleBase(const ComputedStyleBase& o) :
+  {% for field in fields %}
+      {{field.name}}(o.{{field.name}}){{print_if(not loop.last, ',')}}
+  {% endfor %}
+  {}
+
   // Storage.
   {% for field in fields %}
   unsigned {{field.name}} : {{field.size}}; // {{field.type_name}}
   {% endfor %}
 };
 
 } // namespace blink
 
 #endif // ComputedStyleBase_h