Recursively defining custom elements should not lead to redefinition

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScriptCustomElementDefinitionBuilder_h
 #define ScriptCustomElementDefinitionBuilder_h
 
 #include "core/CoreExport.h"
 #include "core/dom/custom/CustomElementDefinitionBuilder.h"
 #include "platform/heap/Handle.h"
@@ skipping 12 matching lines @@
 class CORE_EXPORT ScriptCustomElementDefinitionBuilder
     : public CustomElementDefinitionBuilder {
     STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(ScriptCustomElementDefinitionBuilder);
 public:
     ScriptCustomElementDefinitionBuilder(
         ScriptState*,
         CustomElementsRegistry*,
         const ScriptValue& constructorScriptValue,
         ExceptionState&);
+    ~ScriptCustomElementDefinitionBuilder();
 
     bool checkConstructorIntrinsics() override;
     bool checkConstructorNotRegistered() override;
     bool checkPrototype() override;
     CustomElementDefinition* build(const CustomElementDescriptor&) override;
 
 private:
+    static ScriptCustomElementDefinitionBuilder* s_stack;
+
+    ScriptCustomElementDefinitionBuilder* m_prev;
     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;
 };
 
 } // namespace blink
 
 #endif // ScriptCustomElementDefinitionBuilder_h