[Bindings][Refactoring] Move logics of preparePrototypeAndInterfaceObject from .tmpl to .py

third_party/WebKit/Source/bindings/templates/partial_interface.h.tmpl

 {% filter format_blink_cpp_source_code %}
 
 {% include 'copyright_block.txt' %}
 #ifndef {{v8_class_or_partial}}_h
 #define {{v8_class_or_partial}}_h
 
 {% for filename in header_includes %}
 #include "{{filename}}"
 {% endfor %}
 
@@ skipping 11 matching lines @@
   static void {{method.name}}MethodCustom(const v8::FunctionCallbackInfo<v8::Value>&);
   {% endfor %}
   {% for attribute in attributes %}
   {% if attribute.has_custom_getter %}{# FIXME: and not attribute.implemented_by #}
   static void {{attribute.name}}AttributeGetterCustom(const v8::PropertyCallbackInfo<v8::Value>&);
   {% endif %}
   {% if attribute.has_custom_setter %}{# FIXME: and not attribute.implemented_by #}
   static void {{attribute.name}}AttributeSetterCustom(v8::Local<v8::Value>, const v8::PropertyCallbackInfo<void>&);
   {% endif %}
   {% endfor %}
-  {% if unscopables or has_conditional_attributes_on_prototype or
-        methods | conditionally_exposed(is_partial) %}
+  {% if prepare_prototype_and_interface_object_func %}
   static void preparePrototypeAndInterfaceObject(v8::Local<v8::Context>, const DOMWrapperWorld&, v8::Local<v8::Object>, v8::Local<v8::Function>, v8::Local<v8::FunctionTemplate>);
   {% endif %}
 
   {% for feature in origin_trial_features %}
   static void install{{feature.name}}(ScriptState*, v8::Local<v8::Object> instance);
   static void install{{feature.name}}(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::Object> instance, v8::Local<v8::Object> prototype, v8::Local<v8::Function> interface);
   {% if not feature.needs_instance %}
   static void install{{feature.name}}(ScriptState*);
   {% endif %}
   {% endfor %}
@@ skipping 61 matching lines @@
 
  private:
   static void install{{v8_class}}Template(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::FunctionTemplate> interfaceTemplate);
 };
 
 }  // namespace blink
 
 #endif  // {{v8_class_or_partial}}_h
 
 {% endfilter %}{# format_blink_cpp_source_code #}