Store |detail| as a hidden value of custom event wrappers

third_party/WebKit/Source/core/events/CustomEvent.cpp

Index: third_party/WebKit/Source/core/events/CustomEvent.cpp
diff --git a/third_party/WebKit/Source/core/events/CustomEvent.cpp b/third_party/WebKit/Source/core/events/CustomEvent.cpp
index a9c87cbbdf8ef778d4d06ccfcbf882eef18a330c..3d36eceb99b4817293d67770b971df7546175a0f 100644
--- a/third_party/WebKit/Source/core/events/CustomEvent.cpp
+++ b/third_party/WebKit/Source/core/events/CustomEvent.cpp
@@ -27,6 +27,7 @@
 #include "core/events/CustomEvent.h"
 
 #include "bindings/core/v8/SerializedScriptValue.h"
+#include "bindings/core/v8/SerializedScriptValueFactory.h"
 
 namespace blink {
 
@@ -37,8 +38,6 @@ CustomEvent::CustomEvent()
 CustomEvent::CustomEvent(const AtomicString& type, const CustomEventInit& initializer)
     : Event(type, initializer)
 {
-    if (initializer.hasDetail())
-        m_detail = initializer.detail();
 }
 
 CustomEvent::~CustomEvent()
@@ -48,7 +47,7 @@ CustomEvent::~CustomEvent()
 void CustomEvent::initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable, const ScriptValue& detail)
 {
     initEvent(type, canBubble, cancelable);
-    m_detail = detail;
+    m_serializedDetail = SerializedScriptValueFactory::instance().createAndSwallowExceptions(detail.isolate(), detail.v8Value());
 }
 
 void CustomEvent::initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<SerializedScriptValue> serializedDetail)