Avoid always style recalc when removing stylesheets.

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 5308 matching lines @@
 PassOwnPtr<LifecycleNotifier> Document::createLifecycleNotifier()
 {
     return DocumentLifecycleNotifier::create(this);
 }
 
 DocumentLifecycleNotifier* Document::lifecycleNotifier()
 {
     return static_cast<DocumentLifecycleNotifier*>(ExecutionContext::lifecycleNotifier());
 }
 
+void Document::removedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
+{
+    if (!isActive())
+        return;
+
+    styleEngine()->modifiedStyleSheet(sheet);
+    styleResolverChanged(when, updateMode);
+}
+
+void Document::modifiedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
+{
+    if (!isActive())
+        return;
+
+    styleEngine()->modifiedStyleSheet(sheet);
+    styleResolverChanged(when, updateMode);
+}
+
 } // namespace WebCore