Implement custom element construction and some 'define' checks

third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.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 CustomElementDefinition_h
+#define CustomElementDefinition_h
+
+#include "bindings/core/v8/ScopedPersistent.h"
+#include "platform/heap/Handle.h"
+#include "v8.h"
+#include "wtf/text/AtomicString.h"
+
+namespace blink {
+
+class CustomElementDefinition final
+    : public GarbageCollectedFinalized<CustomElementDefinition> {
+public:
+    CustomElementDefinition(
+        const AtomicString& localName,
+        v8::Isolate*,
+        v8::Local<v8::Object> prototype);
+
+    const AtomicString& localName() const { return m_localName; }
+    v8::Local<v8::Object> prototype(v8::Isolate*) const;

[haraken, 2016/05/11 11:30:09]

Does the performance of prototype() matter?

If not, I'd prefer removing the weak ScopedPersistent. Alternately, you can add
a Member<CustomElementsRegistry>. Then prototype() can look up the prototype
object via the CustomElementsRegistry.

+
+    DEFINE_INLINE_TRACE() { }
+
+private:
+    AtomicString m_localName;
+
+    // This is a weak reference. CustomElementDefinition can rely on
+    // it being kept alive as long as the CustomElementsRegistry which
+    // owns this definition is alive:
+    // CustomElementsRegistry wrapper ---> ::m_constructorIdMap
+    // m_constructorIdMap --- key ---> constructor
+    // constructor --- prototype propery ---> m_prototype
+    ScopedPersistent<v8::Object> m_prototype;
+};
+
+} // namespace blink
+
+#endif // CustomElementDefinition_h