Don't create an empty text node when setting document.title to the empty string

Source/core/html/HTMLTitleElement.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, 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 71 matching lines @@
 
     return result.toString();
 }
 
 void HTMLTitleElement::setText(const String &value)
 {
     RefPtr<Node> protectFromMutationEvents(this);
     ChildListMutationScope mutation(*this);
 
     // Avoid calling Document::setTitleElement() during intermediate steps.
-    m_ignoreTitleUpdatesWhenChildrenChange = true;
+    m_ignoreTitleUpdatesWhenChildrenChange = !value.isEmpty();
     removeChildren();
     m_ignoreTitleUpdatesWhenChildrenChange = false;
 
-    appendChild(document().createTextNode(value.impl()), IGNORE_EXCEPTION);
+    if (!value.isEmpty())
+        appendChild(document().createTextNode(value.impl()), IGNORE_EXCEPTION);
 }
 
 }