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

Source/core/css/CSSStyleSheet.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 62 matching lines @@
 PassRefPtr<CSSStyleSheet> CSSStyleSheet::create(PassRefPtr<StyleSheetContents> sheet, CSSImportRule* ownerRule)
 {
     return adoptRef(new CSSStyleSheet(sheet, ownerRule));
 }
 
 PassRefPtr<CSSStyleSheet> CSSStyleSheet::create(PassRefPtr<StyleSheetContents> sheet, Node* ownerNode)
 {
     return adoptRef(new CSSStyleSheet(sheet, ownerNode, false, TextPosition::minimumPosition()));
 }
 
+PassRefPtr<CSSStyleSheet> CSSStyleSheet::createInline(PassRefPtr<StyleSheetContents> sheet, Node* ownerNode, const TextPosition& startPosition)
+{
+    ASSERT(sheet);
+    return adoptRef(new CSSStyleSheet(sheet, ownerNode, true, startPosition));
+}
+
 PassRefPtr<CSSStyleSheet> CSSStyleSheet::createInline(Node* ownerNode, const KURL& baseURL, const TextPosition& startPosition, const String& encoding)
 {
     CSSParserContext parserContext(ownerNode->document(), baseURL, encoding);
     RefPtr<StyleSheetContents> sheet = StyleSheetContents::create(baseURL.string(), parserContext);
     return adoptRef(new CSSStyleSheet(sheet.release(), ownerNode, true, startPosition));
 }
 
 CSSStyleSheet::CSSStyleSheet(PassRefPtr<StyleSheetContents> contents, CSSImportRule* ownerRule)
     : m_contents(contents)
     , m_isInlineStylesheet(false)
     , m_isDisabled(false)
     , m_ownerNode(0)
     , m_ownerRule(ownerRule)
     , m_startPosition(TextPosition::minimumPosition())
+    , m_loadCompleted(false)
 {
     m_contents->registerClient(this);
 }
 
 CSSStyleSheet::CSSStyleSheet(PassRefPtr<StyleSheetContents> contents, Node* ownerNode, bool isInlineStylesheet, const TextPosition& startPosition)
     : m_contents(contents)
     , m_isInlineStylesheet(isInlineStylesheet)
     , m_isDisabled(false)
     , m_ownerNode(ownerNode)
     , m_ownerRule(0)
     , m_startPosition(startPosition)
+    , m_loadCompleted(false)
 {
     ASSERT(isAcceptableCSSStyleSheetParent(ownerNode));
     m_contents->registerClient(this);
 }
 
 CSSStyleSheet::~CSSStyleSheet()
 {
     // For style rules outside the document, .parentStyleSheet can become null even if the style rule
     // is still observable from JavaScript. This matches the behavior of .parentNode for nodes, but
     // it's not ideal because it makes the CSSOM's behavior depend on the timing of garbage collection.
     for (unsigned i = 0; i < m_childRuleCSSOMWrappers.size(); ++i) {
         if (m_childRuleCSSOMWrappers[i])
             m_childRuleCSSOMWrappers[i]->setParentStyleSheet(0);
     }
 
     if (m_mediaCSSOMWrapper)
         m_mediaCSSOMWrapper->clearParentStyleSheet();
 
     m_contents->unregisterClient(this);
 }
 
 void CSSStyleSheet::willMutateRules()
 {
     InspectorInstrumentation::willMutateRules(this);
     // If we are the only client it is safe to mutate.
     if (m_contents->hasOneClient() && !m_contents->isInMemoryCache()) {
         m_contents->clearRuleSet();
+        if (m_contents->maybeCacheable())
+            StyleEngine::removeSheet(m_contents.get());
         m_contents->setMutable();
         return;
     }
     // Only cacheable stylesheets should have multiple clients.
     ASSERT(m_contents->isCacheable());
 
     // Copy-on-write.
     m_contents->unregisterClient(this);
     m_contents = m_contents->copy();
     m_contents->registerClient(this);
@@ skipping 229 matching lines @@
     while (root->parentStyleSheet())
         root = root->parentStyleSheet();
     return root->ownerNode() ? &root->ownerNode()->document() : 0;
 }
 
 void CSSStyleSheet::clearChildRuleCSSOMWrappers()
 {
     m_childRuleCSSOMWrappers.clear();
 }
 
+bool CSSStyleSheet::sheetLoaded()
+{
+    m_loadCompleted = m_ownerNode->sheetLoaded();
+    return m_loadCompleted;
 }
+
+void CSSStyleSheet::startLoadingDynamicSheet()
+{
+    m_loadCompleted = false;
+    m_ownerNode->startLoadingDynamicSheet();
+}
+
+}