Limit the usage of SharedPersistent to ScriptValue only

Source/core/html/HTMLPlugInElement.cpp

Index: Source/core/html/HTMLPlugInElement.cpp
diff --git a/Source/core/html/HTMLPlugInElement.cpp b/Source/core/html/HTMLPlugInElement.cpp
index 0b2df23c31693eb216d32f4f308cd4248aba55c8..883ccb6b6fcd5e789b739d48cae7be35a3d826be 100644
--- a/Source/core/html/HTMLPlugInElement.cpp
+++ b/Source/core/html/HTMLPlugInElement.cpp
@@ -74,7 +74,7 @@ HTMLPlugInElement::HTMLPlugInElement(const QualifiedName& tagName, Document& doc
 
 HTMLPlugInElement::~HTMLPlugInElement()
 {
-    ASSERT(!m_pluginWrapper); // cleared in detach()
+    ASSERT(m_pluginWrapper.hasNoValue()); // cleared in detach()
     ASSERT(!m_isDelayingLoadEvent);
 
     if (m_NPObject) {
@@ -209,20 +209,20 @@ void HTMLPlugInElement::resetInstance()
     m_pluginWrapper.clear();
 }
 
-SharedPersistent<v8::Object>* HTMLPlugInElement::pluginWrapper()
+ScriptValue HTMLPlugInElement::pluginWrapper()
 {
     Frame* frame = document().frame();
     if (!frame)
-        return 0;
+        return ScriptValue();
 
     // If the host dynamically turns off JavaScript (or Java) we will still
     // return the cached allocated Bindings::Instance. Not supporting this
     // edge-case is OK.
-    if (!m_pluginWrapper) {
+    if (m_pluginWrapper.hasNoValue()) {
         if (Widget* widget = pluginWidget())
             m_pluginWrapper = frame->script().createPluginWrapper(widget);
     }
-    return m_pluginWrapper.get();
+    return m_pluginWrapper;
 }
 
 bool HTMLPlugInElement::dispatchBeforeLoadEvent(const String& sourceURL)