Remove leak of objects between isolated worlds on custom events.

Source/core/dom/CustomEvent.cpp

Index: Source/core/dom/CustomEvent.cpp
diff --git a/Source/core/dom/CustomEvent.cpp b/Source/core/dom/CustomEvent.cpp
index c7e67b3eb97a9e9f44106767f0457f359c2fa9ab..eb7c4fb033b1251998cfad620e92a9def85425eb 100644
--- a/Source/core/dom/CustomEvent.cpp
+++ b/Source/core/dom/CustomEvent.cpp
@@ -41,7 +41,6 @@ CustomEvent::CustomEvent()
 
 CustomEvent::CustomEvent(const AtomicString& type, const CustomEventInit& initializer)
     : Event(type, initializer)
-    , m_detail(initializer.detail)
 {
     ScriptWrappable::init(this);
 }
@@ -50,20 +49,17 @@ CustomEvent::~CustomEvent()
 {
 }
 
-void CustomEvent::initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable, const ScriptValue& detail)
+void CustomEvent::initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable)
 {
     ASSERT(!m_serializedScriptValue.get());
     if (dispatched())
         return;
 
     initEvent(type, canBubble, cancelable);
-
-    m_detail = detail;
 }
 
 void CustomEvent::initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<SerializedScriptValue> serializedScriptValue)
 {
-    ASSERT(m_detail.hasNoValue());
     if (dispatched())
         return;