Implement languagechange event, fired when accept languages changes.

Source/core/html/HTMLBodyElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann (hausmann@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 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
@@ skipping 131 matching lines @@
     else if (name == onscrollAttr)
         document().setWindowAttributeEventListener(EventTypeNames::scroll, createAttributeEventListener(document().frame(), name, value));
     else if (name == onselectionchangeAttr)
         document().setAttributeEventListener(EventTypeNames::selectionchange, createAttributeEventListener(document().frame(), name, value));
     else if (name == onstorageAttr)
         document().setWindowAttributeEventListener(EventTypeNames::storage, createAttributeEventListener(document().frame(), name, value));
     else if (name == ononlineAttr)
         document().setWindowAttributeEventListener(EventTypeNames::online, createAttributeEventListener(document().frame(), name, value));
     else if (name == onofflineAttr)
         document().setWindowAttributeEventListener(EventTypeNames::offline, createAttributeEventListener(document().frame(), name, value));
+    else if (name == onlanguagechangeAttr)
+        document().setWindowAttributeEventListener(EventTypeNames::languagechange, createAttributeEventListener(document().frame(), name, value));
     else
         HTMLElement::parseAttribute(name, value);
 }
 
 Node::InsertionNotificationRequest HTMLBodyElement::insertedInto(ContainerNode* insertionPoint)
 {
     HTMLElement::insertedInto(insertionPoint);
     return InsertionShouldCallDidNotifySubtreeInsertions;
 }
 
@@ skipping 160 matching lines @@
 double HTMLBodyElement::scrollWidth()
 {
     // Update the document's layout.
     Document& document = this->document();
     document.updateLayoutIgnorePendingStylesheets();
     FrameView* view = document.view();
     return view ? adjustForZoom(view->contentsWidth(), &document) : 0;
 }
 
 } // namespace WebCore