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

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index ab1e4efa16585612da3153947a4803a48e31b440..d88b3622e9eb3cbe2b8ddf890e75727da5f7e4bd 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -496,6 +496,8 @@ Document::~Document()
     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().
 
@@ -627,6 +629,7 @@ void Document::setCompatibilityMode(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();
     }
 }