Correct handling of |for| and |event| attributes of script elements.

Source/core/dom/ScriptLoader.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 464 matching lines @@
 
 bool ScriptLoader::ignoresLoadRequest() const
 {
     return m_alreadyStarted || m_isExternalScript || m_parserInserted || !element() || !element()->inDocument();
 }
 
 bool ScriptLoader::isScriptForEventSupported() const
 {
     String eventAttribute = client()->eventAttributeValue();
     String forAttribute = client()->forAttributeValue();
-    if (!eventAttribute.isEmpty() && !forAttribute.isEmpty()) {
-        forAttribute = forAttribute.stripWhiteSpace();
-        if (!equalIgnoringCase(forAttribute, "window"))
-            return false;
+    if (eventAttribute.isNull() || forAttribute.isNull())

[tkent, 2015/09/02 07:37:31]

This change might look complex, but it's
 - Replacing isEmpty() with isNull()
 - Applying early return.

[kochi, 2015/09/02 07:47:07]

Acknowledged.

+        return true;
 
-        eventAttribute = eventAttribute.stripWhiteSpace();
-        if (!equalIgnoringCase(eventAttribute, "onload") && !equalIgnoringCase(eventAttribute, "onload()"))
-            return false;
-    }
-    return true;
+    forAttribute = forAttribute.stripWhiteSpace();
+    if (!equalIgnoringCase(forAttribute, "window"))
+        return false;
+    eventAttribute = eventAttribute.stripWhiteSpace();
+    return equalIgnoringCase(eventAttribute, "onload") || equalIgnoringCase(eventAttribute, "onload()");
 }
 
 String ScriptLoader::scriptContent() const
 {
     return m_element->textFromChildren();
 }
 
 ScriptLoaderClient* ScriptLoader::client() const
 {
     if (isHTMLScriptLoader(m_element))
@@ skipping 11 matching lines @@
     if (isHTMLScriptLoader(element))
         return toHTMLScriptElement(element)->loader();
 
     if (isSVGScriptLoader(element))
         return toSVGScriptElement(element)->loader();
 
     return 0;
 }
 
 } // namespace blink