Do not push the custom element construction stack in some cases.

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.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 ScriptCustomElementDefinition_h
 #define ScriptCustomElementDefinition_h
 
 #include "bindings/core/v8/ScopedPersistent.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/CoreExport.h"
@@ skipping 55 matching lines @@
       const v8::Local<v8::Object>& constructor,
       const v8::Local<v8::Function>& connectedCallback,
       const v8::Local<v8::Function>& disconnectedCallback,
       const v8::Local<v8::Function>& adoptedCallback,
       const v8::Local<v8::Function>& attributeChangedCallback,
       const HashSet<AtomicString>& observedAttributes);
 
   // Implementations of |CustomElementDefinition|
   ScriptValue getConstructorForScript() final;
   bool runConstructor(Element*) override;
-  Element* runConstructor();
+
+  // Calls the constructor. The script scope, etc. must already be set up.
+  Element* callConstructor();
 
   void runCallback(v8::Local<v8::Function>,
                    Element*,
                    int argc = 0,
                    v8::Local<v8::Value> argv[] = nullptr);
 
   HTMLElement* handleCreateElementSyncException(Document&,
                                                 const QualifiedName& tagName,
                                                 v8::Isolate*,
                                                 ExceptionState&);
 
   RefPtr<ScriptState> m_scriptState;
   ScopedPersistent<v8::Object> m_constructor;
   ScopedPersistent<v8::Function> m_connectedCallback;
   ScopedPersistent<v8::Function> m_disconnectedCallback;
   ScopedPersistent<v8::Function> m_adoptedCallback;
   ScopedPersistent<v8::Function> m_attributeChangedCallback;
 };
 
 }  // namespace blink
 
 #endif  // ScriptCustomElementDefinition_h