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

Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp

Index: Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp
diff --git a/Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp b/Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp
index 7f8243f40dacb1bb292f110a8aaeace12558071c..0813bbce1cb6a9c707c6456e3a7fc3b8ea21ac09 100644
--- a/Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp
+++ b/Source/WebCore/Modules/webaudio/OfflineAudioCompletionEvent.cpp
@@ -45,13 +45,14 @@ PassRefPtr<OfflineAudioCompletionEvent> OfflineAudioCompletionEvent::create(Pass
 
 OfflineAudioCompletionEvent::OfflineAudioCompletionEvent()
 {
+    ScriptWrappable::init(this);
 }
 
-
 OfflineAudioCompletionEvent::OfflineAudioCompletionEvent(PassRefPtr<AudioBuffer> renderedBuffer)
     : Event(eventNames().completeEvent, true, false)
     , m_renderedBuffer(renderedBuffer)
 {
+    ScriptWrappable::init(this);
 }
 
 OfflineAudioCompletionEvent::~OfflineAudioCompletionEvent()