Make ComputedStyleBase a templated class to allow it to use functions on ComputedStyle

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

 {% from 'macros.tmpl' import license, print_if %}
 {% from 'fields/field.tmpl' import encode, getter_expression, setter_expression, declare_storage, fieldwise_compare, fieldwise_copy, fieldwise_diff %}
 {% from 'fields/group.tmpl' import define_field_group_class %}
 {{license()}}
 
 #ifndef ComputedStyleBase_h
 #define ComputedStyleBase_h
 
 #include "core/style/ComputedStyleConstants.h"
 #include "core/CoreExport.h"
@@ skipping 28 matching lines @@
   void* dataRefs[{{computed_style.subgroups|length}}];
   {% endif %}
   {% for field in computed_style.fields|rejectattr("is_bit_field") %}
   {{field.type_name}} {{field.name}};
   {% endfor %}
   unsigned m_bit_fields[{{computed_style.num_32_bit_words_for_bit_fields}}];
 };
 
 // The generated portion of ComputedStyle. For more info, see the header comment
 // in ComputedStyle.h.
+
+// ComputedStyleBase is a templated class to allow it to use functions
+// on ComputedStyle. This allows ComputedStyleBase to use hand written 
+// functions it would otherwise not know about.
+// It should only be templated with the ComputedStyle class and no other class
+// is allowed.
+template <class ComputedStyleFinal>
 class CORE_EXPORT ComputedStyleBase {
  public:
   inline bool IndependentInheritedEqual(const ComputedStyleBase& o) const {
     return (
         {{fieldwise_compare(computed_style, computed_style.all_fields
             |selectattr("is_property")
             |selectattr("is_inherited")
             |selectattr("is_independent")
             |list
           )|indent(8)}}
@@ skipping 56 matching lines @@
   // style that are marked as inherited by this style.
   void PropagateIndependentInheritedProperties(
       const ComputedStyleBase& parentStyle) {
     {% for field in computed_style.all_fields if field.is_property and field.is_independent %}
     if ({{field.is_inherited_method_name}}())
       {{setter_expression(field)}} = parentStyle.{{getter_expression(field)}};
     {% endfor %}
   }
 
   {% for name, groups_to_diff in diff_functions_map.items() %}
-  bool {{name}}(const ComputedStyleBase& other) const {
+  bool {{name}}(const ComputedStyleFinal& other) const {
     {{fieldwise_diff(groups_to_diff)|indent(4)}}
     return false;
   }
   {% endfor %}
 
   // Fields.
   // TODO(sashab): Remove initialFoo() static methods and update callers to
   // use resetFoo(), which can be more efficient.
 
   {% for field in computed_style.all_fields %}
@@ skipping 40 matching lines @@
     return static_cast<unsigned>(std::min<float>(width, kMaxForBorderWidth) *
                                  kBorderWidthDenominator);
   }
 
  private:
   {% for field in computed_style.fields %}
   {{declare_storage(field)}}
   {% endfor %}
 };
 
-// If this fails, the packing algorithm in make_computed_style_base.py has
-// failed to produce the optimal packed size. To fix, update the algorithm to
-// ensure that the buckets are placed so that each takes up at most 1 word.
-ASSERT_SIZE(ComputedStyleBase, SameSizeAsComputedStyleBase);
-
 } // namespace blink
 
 #endif // ComputedStyleBase_h