Disallow wrapper creation from visitDOMWrapper

Source/bindings/templates/interface.cpp

 {% extends 'interface_base.cpp' %}
 
 
 {##############################################################################}
 {% block indexed_property_getter %}
 {% if indexed_property_getter and not indexed_property_getter.is_custom %}
 {% set getter = indexed_property_getter %}
 static void indexedPropertyGetter(uint32_t index, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
     {{cpp_class}}* impl = {{v8_class}}::toImpl(info.Holder());
@@ skipping 578 matching lines @@
 {% if reachable_node_function or set_wrapper_reference_to_list %}
 void {{v8_class}}::visitDOMWrapper(v8::Isolate* isolate, ScriptWrappable* scriptWrappable, const v8::Persistent<v8::Object>& wrapper)
 {
     {{cpp_class}}* impl = scriptWrappable->toImpl<{{cpp_class}}>();
     {% if set_wrapper_reference_to_list %}
     v8::Local<v8::Object> creationContext = v8::Local<v8::Object>::New(isolate, wrapper);
     V8WrapperInstantiationScope scope(creationContext, isolate);
     {% for set_wrapper_reference_to in set_wrapper_reference_to_list %}
     {{set_wrapper_reference_to.cpp_type}} {{set_wrapper_reference_to.name}} = impl->{{set_wrapper_reference_to.name}}();
     if ({{set_wrapper_reference_to.name}}) {
-        if (!DOMDataStore::containsWrapper({{set_wrapper_reference_to.name}}, isolate))
-            {{set_wrapper_reference_to.name}}->wrap(creationContext, isolate);

[haraken, 2015/02/16 03:56:49]

Another idea would be just to skip creating a wrapper (and setting a reference)
if the target wrapper does not exist. Will it work?

[kouhei (in TOK), 2015/02/16 04:03:24]

Wouldn't it be too fragile? I prefer an ASSERT here.

+        ASSERT(DOMDataStore::containsWrapper({{set_wrapper_reference_to.name}}, isolate));
         DOMDataStore::setWrapperReference(wrapper, {{set_wrapper_reference_to.name}}, isolate);
     }
     {% endfor %}
     {% endif %}
     {% if reachable_node_function %}
     // The {{reachable_node_function}}() method may return a reference or a pointer.
     if (Node* owner = WTF::getPtr(impl->{{reachable_node_function}}())) {
         Node* root = V8GCController::opaqueRootForGC(isolate, owner);
         isolate->SetReferenceFromGroup(v8::UniqueId(reinterpret_cast<intptr_t>(root)), wrapper);
         return;
@@ skipping 368 matching lines @@
 }
 
 {% for method in methods if method.overloads and method.overloads.has_partial_overloads %}
 void {{v8_class}}::register{{method.name | blink_capitalize}}MethodForPartialInterface(void (*method)(const v8::FunctionCallbackInfo<v8::Value>&))
 {
     {{cpp_class}}V8Internal::{{method.name}}MethodForPartialInterface = method;
 }
 {% endfor %}
 {% endif %}
 {% endblock %}