Workaround 75604 for m15

Source/WebCore/dom/ScriptElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * 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
@@ skipping 313 matching lines @@
         dispatchErrorEvent();
     else if (!cachedScript->wasCanceled()) {
         executeScript(ScriptSourceCode(cachedScript));
         dispatchLoadEvent();
     }
     cachedScript->removeClient(this);
 }
 
 void ScriptElement::notifyFinished(CachedResource* o)
 {
+    // crbug.com/75604 causes double notification in some situations, disregarding the second notification
+    // is a workaround.
+    if (!m_cachedScript)
+        return;
+
     ASSERT(!m_willBeParserExecuted);
     ASSERT_UNUSED(o, o == m_cachedScript);
     if (m_willExecuteInOrder)
         m_element->document()->scriptRunner()->notifyInOrderScriptReady();
     else
         m_element->document()->scriptRunner()->queueScriptForExecution(this, m_cachedScript, ScriptRunner::ASYNC_EXECUTION);
 
 #if PLATFORM(CHROMIUM)
     ASSERT(m_cachedScriptState == Set);
     m_cachedScriptState = ZeroedInNotifyFinished;
@@ skipping 58 matching lines @@
 
 #if ENABLE(SVG)
     if (element->isSVGElement() && element->hasTagName(SVGNames::scriptTag))
         return static_cast<SVGScriptElement*>(element);
 #endif
 
     return 0;
 }
 
 }