Recursively defining custom elements should not lead to redefinition

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h

Index: third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h
index b6d98ab1cee403410831c3e29a54a7eb8af56ff2..500a41dcdd04784dd0aea6c71595fe328f76daac 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.h
@@ -30,6 +30,7 @@ public:
         CustomElementsRegistry*,
         const ScriptValue& constructorScriptValue,
         ExceptionState&);
+    virtual ~ScriptCustomElementDefinitionBuilder();
 
     bool checkConstructorIntrinsics() override;
     bool checkConstructorNotRegistered() override;
@@ -37,12 +38,15 @@ public:
     CustomElementDefinition* build(const CustomElementDescriptor&) override;
 
 private:
+    v8::Local<v8::Set> constructorsBeingDefined();
+
     RefPtr<ScriptState> m_scriptState;
     Member<CustomElementsRegistry> m_registry;
     v8::Local<v8::Value> m_constructorValue;
     v8::Local<v8::Object> m_constructor;
     v8::Local<v8::Object> m_prototype;
     ExceptionState& m_exceptionState;
+    bool m_didStartDefiningConstructor;
 };
 
 } // namespace blink