First part of work to move V8 binding integrity off of vtables.

Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp

Index: Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp
diff --git a/Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp b/Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp
index 950fadd3b5d048616e8f08a77a6b4e36019c8e07..94a4e43cc1f932d91bb29afe270a552534e3d661 100644
--- a/Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp
+++ b/Source/WebCore/Modules/mediastream/MediaStreamEvent.cpp
@@ -54,18 +54,21 @@ PassRefPtr<MediaStreamEvent> MediaStreamEvent::create(const AtomicString& type,
 
 MediaStreamEvent::MediaStreamEvent()
 {
+    ScriptWrappable::init(this);
 }
 
 MediaStreamEvent::MediaStreamEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<MediaStream> stream)
     : Event(type, canBubble, cancelable)
     , m_stream(stream)
 {
+    ScriptWrappable::init(this);
 }
 
 MediaStreamEvent::MediaStreamEvent(const AtomicString& type, const MediaStreamEventInit& initializer)
     : Event(type, initializer)
     , m_stream(initializer.stream)
 {
+    ScriptWrappable::init(this);
 }
 
 MediaStreamEvent::~MediaStreamEvent()