Freeze global prototype chain per WebIDL

third_party/WebKit/Source/bindings/templates/interface.cpp.tmpl

 {% extends 'interface_base.cpp.tmpl' %}
 
 {% set has_prepare_prototype_and_interface_object =
     unscopables or has_conditional_attributes_on_prototype or
     methods | conditionally_exposed(is_partial) %}
 {% set prepare_prototype_and_interface_object_func =
     '%s::preparePrototypeAndInterfaceObject' % v8_class
     if has_prepare_prototype_and_interface_object
     else 'nullptr' %}
 
@@ skipping 775 matching lines @@
 v8::Local<v8::FunctionTemplate> {{v8_class}}::domTemplateForNamedPropertiesObject(v8::Isolate* isolate, const DOMWrapperWorld& world)
 {
     v8::Local<v8::FunctionTemplate> parentTemplate = V8{{parent_interface}}::domTemplate(isolate, world);
 
     v8::Local<v8::FunctionTemplate> namedPropertiesObjectFunctionTemplate = v8::FunctionTemplate::New(isolate, V8ObjectConstructor::isValidConstructorMode);
     namedPropertiesObjectFunctionTemplate->SetClassName(v8AtomicString(isolate, "{{interface_name}}Properties"));
     namedPropertiesObjectFunctionTemplate->Inherit(parentTemplate);
 
     v8::Local<v8::ObjectTemplate> namedPropertiesObjectTemplate = namedPropertiesObjectFunctionTemplate->PrototypeTemplate();
     namedPropertiesObjectTemplate->SetInternalFieldCount({{v8_class}}::internalFieldCount);
+    // Named Properties object has SetPrototype method of Immutable Prototype Exotic Objects
+    namedPropertiesObjectTemplate->SetImmutableProto();
     V8DOMConfiguration::setClassString(isolate, namedPropertiesObjectTemplate, "{{interface_name}}Properties");
     {{install_named_property_handler('namedPropertiesObjectTemplate') | indent}}
 
     return namedPropertiesObjectFunctionTemplate;
 }
 
 {% endif %}
 {% endblock %}
 
 
@@ skipping 186 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 %}