Avoid parsing css text if there are identical inline style blocks.

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 478 matching lines @@
     m_lifecyle.advanceTo(DocumentLifecycle::Inactive);
 }
 
 Document::~Document()
 {
     ASSERT(!renderView());
     ASSERT(m_ranges.isEmpty());
     ASSERT(!m_parentTreeScope);
     ASSERT(!hasGuardRefCount());
 
+    StyleEngine::clearSheetCache();

[esprehn, 2013/11/15 10:27:37]

You shouldn't need to clear the sheet cache like this, the when the owner nodes
are freed they should drop their refs and the result should clear the cache.

[tasak, 2014/01/09 09:24:50]

Done.

+
     if (m_templateDocument)
         m_templateDocument->setTemplateDocumentHost(0); // balanced in templateDocument().
 
     if (Document* ownerDocument = this->ownerDocument())
         ownerDocument->didRemoveEventTargetNode(this);
 
     m_scriptRunner.clear();
 
     removeAllEventListeners();
 
@@ skipping 111 matching lines @@
 
 void Document::setCompatibilityMode(CompatibilityMode mode)
 {
     if (m_compatibilityModeLocked || mode == m_compatibilityMode)
         return;
     bool wasInQuirksMode = inQuirksMode();
     m_compatibilityMode = mode;
     selectorQueryCache().invalidate();
     if (inQuirksMode() != wasInQuirksMode) {
         // All injected stylesheets have to reparse using the different mode.
+        StyleEngine::clearSheetCache();

[esprehn, 2013/11/15 10:27:37]

Ditto.

[tasak, 2014/01/09 09:24:50]

I think, quirks document cannot share stylesheets with non-quirks document,
because CSSGrammar.y and BinsonCSSParser-in.cpp check whether parserContext mode
is quirksMode or not while parsing styles.

i.e. isQuirksModeBehavior(), inQuirksMode() and so on.

         m_styleEngine->invalidateInjectedStyleSheetCache();
     }
 }
 
 String Document::compatMode() const
 {
     return inQuirksMode() ? "BackCompat" : "CSS1Compat";
 }
 
 void Document::setDoctype(PassRefPtr<DocumentType> docType)
@@ skipping 4548 matching lines @@
 void Document::modifiedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
 {
     if (!isActive())
         return;
 
     styleEngine()->modifiedStyleSheet(sheet);
     styleResolverChanged(when, updateMode);
 }
 
 } // namespace WebCore