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

Source/core/dom/StyleEngine.h

Index: Source/core/dom/StyleEngine.h
diff --git a/Source/core/dom/StyleEngine.h b/Source/core/dom/StyleEngine.h
index 1d0ca78f475876c16c194360f4e23a03caac33d1..042fa1b11471941871c3fe9ed65243abe7255fbf 100644
--- a/Source/core/dom/StyleEngine.h
+++ b/Source/core/dom/StyleEngine.h
@@ -175,6 +175,9 @@ public:
     void collectDocumentActiveStyleSheets(StyleSheetCollectionBase&);
     void markDocumentDirty();
 
+    static PassRefPtr<CSSStyleSheet> createSheet(Element*, const String& text, TextPosition startPosition, bool createdByParser);
+    static void removeSheet(StyleSheetContents*);
+
 private:
     StyleEngine(Document&);
 
@@ -197,6 +200,8 @@ private:
     void notifyPendingStyleSheetAdded();
     void notifyPendingStyleSheetRemoved(RemovePendingSheetNotificationType);
 
+    static PassRefPtr<CSSStyleSheet> parseSheet(Element*, const String& text, TextPosition startPosition, bool createdByParser);
+
     Document& m_document;
     bool m_isMaster;