ServiceWorker: Add initial implementation of ExtendableMessageEvent behind a flag

third_party/WebKit/Source/modules/serviceworkers/ExtendableMessageEvent.h

Index: third_party/WebKit/Source/modules/serviceworkers/ExtendableMessageEvent.h
diff --git a/third_party/WebKit/Source/modules/serviceworkers/ExtendableMessageEvent.h b/third_party/WebKit/Source/modules/serviceworkers/ExtendableMessageEvent.h
new file mode 100644
index 0000000000000000000000000000000000000000..37bea5b6db2d5f6991f1fd135a19087b948a32ab
--- /dev/null
+++ b/third_party/WebKit/Source/modules/serviceworkers/ExtendableMessageEvent.h
@@ -0,0 +1,35 @@
+// 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 ExtendableMessageEvent_h
+#define ExtendableMessageEvent_h
+
+#include "modules/EventModules.h"
+#include "modules/ModulesExport.h"
+#include "modules/serviceworkers/ExtendableEvent.h"
+#include "modules/serviceworkers/ExtendableMessageEventInit.h"
+
+namespace blink {
+
+class MODULES_EXPORT ExtendableMessageEvent final : public ExtendableEvent {
+    DEFINE_WRAPPERTYPEINFO();
+
+public:
+    static PassRefPtrWillBeRawPtr<ExtendableMessageEvent> create();
+    static PassRefPtrWillBeRawPtr<ExtendableMessageEvent> create(const AtomicString& type, const ExtendableMessageEventInit& initializer);
+    static PassRefPtrWillBeRawPtr<ExtendableMessageEvent> create(const AtomicString& type, const ExtendableMessageEventInit& initializer, WaitUntilObserver*);
+
+    const AtomicString& interfaceName() const override;
+
+    DECLARE_VIRTUAL_TRACE();
+
+private:
+    ExtendableMessageEvent();
+    ExtendableMessageEvent(const AtomicString& type, const ExtendableMessageEventInit& initializer);
+    ExtendableMessageEvent(const AtomicString& type, const ExtendableMessageEventInit& initializer, WaitUntilObserver*);
+};
+
+} // namespace blink
+
+#endif // ExtendableMessageEvent_h