Don't install private script class without a context document

Source/core/html/HTMLMarqueeElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2007, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 16 matching lines @@
 #include "bindings/core/v8/V8HTMLMarqueeElement.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/frame/UseCounter.h"
 
 namespace blink {
 
 inline HTMLMarqueeElement::HTMLMarqueeElement(Document& document)
     : HTMLElement(HTMLNames::marqueeTag, document)
 {
-    v8::Handle<v8::Value> classObject = PrivateScriptRunner::installClassIfNeeded(&document, "HTMLMarqueeElement");
-    RELEASE_ASSERT(!classObject.IsEmpty());
+    if (document.contextDocument()) {
+        v8::Handle<v8::Value> classObject = PrivateScriptRunner::installClassIfNeeded(&document, "HTMLMarqueeElement");
+        RELEASE_ASSERT(!classObject.IsEmpty());
+    }
     UseCounter::count(document, UseCounter::HTMLMarqueeElement);
 }
 
 PassRefPtrWillBeRawPtr<HTMLMarqueeElement> HTMLMarqueeElement::create(Document& document)
 {
     RefPtrWillBeRawPtr<HTMLMarqueeElement> marqueeElement(adoptRefWillBeNoop(new HTMLMarqueeElement(document)));
     V8HTMLMarqueeElement::PrivateScript::createdCallbackMethod(document.frame(), marqueeElement.get());
     return marqueeElement.release();
 }
 
@@ skipping 14 matching lines @@
 
 void HTMLMarqueeElement::removedFrom(ContainerNode* insertionPoint)
 {
     HTMLElement::removedFrom(insertionPoint);
     if (insertionPoint->inDocument()) {
         V8HTMLMarqueeElement::PrivateScript::detachedCallbackMethod(insertionPoint->document().frame(), this);
     }
 }
 
 } // namespace blink