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

Source/core/css/StyleSheetContentsCache.h

Index: Source/core/css/StyleSheetContentsCache.h
diff --git a/Source/core/css/resolver/MatchedPropertiesCache.h b/Source/core/css/StyleSheetContentsCache.h
similarity index 51%
copy from Source/core/css/resolver/MatchedPropertiesCache.h
copy to Source/core/css/StyleSheetContentsCache.h
index 2e5297d5acd3c4bf14d2ca3cf161c2e593370ba6..067aea341e9b9a905135a0db6b17250ceeabd8c6 100644
--- a/Source/core/css/resolver/MatchedPropertiesCache.h
+++ b/Source/core/css/StyleSheetContentsCache.h
@@ -20,54 +20,52 @@
  *
  */
 
-#ifndef MatchedPropertiesCache_h
-#define MatchedPropertiesCache_h
-
-#include "core/css/resolver/MatchResult.h"
+#ifndef StyleSheetContentsCache_h
+#define StyleSheetContentsCache_h
 
+#include "core/css/StyleSheetContents.h"
 #include "platform/Timer.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/Noncopyable.h"
+#include "wtf/RefPtr.h"
+#include "wtf/text/AtomicString.h"
 
 namespace WebCore {
 
-class RenderStyle;
-class StyleResolverState;
+class StyleSheetContents;
+
+class StyleSheetContentsCacheItem : public RefCounted<StyleSheetContentsCacheItem> {
+public:
+    static PassRefPtr<StyleSheetContentsCacheItem> create(StyleSheetContents*);
 
-struct CachedMatchedProperties {
-    Vector<MatchedProperties> matchedProperties;
-    MatchRanges ranges;
-    RefPtr<RenderStyle> renderStyle;
-    RefPtr<RenderStyle> parentRenderStyle;
+    StyleSheetContents* contents() { return m_contents.get(); }
 
-    void set(const RenderStyle*, const RenderStyle* parentStyle, const MatchResult&);
-    void clear();
+private:
+    StyleSheetContentsCacheItem(PassRefPtr<StyleSheetContents> contents) : m_contents(contents) { }
+
+    RefPtr<StyleSheetContents> m_contents;
 };
 
-class MatchedPropertiesCache {
-    WTF_MAKE_NONCOPYABLE(MatchedPropertiesCache);
+class StyleSheetContentsCache {
+    WTF_MAKE_NONCOPYABLE(StyleSheetContentsCache);
 public:
-    MatchedPropertiesCache();
-
-    const CachedMatchedProperties* find(unsigned hash, const StyleResolverState&, const MatchResult&);
-    void add(const RenderStyle*, const RenderStyle* parentStyle, unsigned hash, const MatchResult&);
+    StyleSheetContentsCache();
 
+    StyleSheetContents* find(const AtomicString& sheetText);
+    void add(const AtomicString& sheetText, StyleSheetContents*);
+    void remove(const AtomicString& sheetText);
     void clear();
 
-    static bool isCacheable(const Element*, const RenderStyle*, const RenderStyle* parentStyle);
-
 private:
-    // Every N additions to the matched declaration cache trigger a sweep where entries holding
-    // the last reference to a style declaration are garbage collected.
-    void sweep(Timer<MatchedPropertiesCache>*);
+    void sweep(Timer<StyleSheetContentsCache>*);
 
     unsigned m_additionsSinceLastSweep;
 
-    typedef HashMap<unsigned, OwnPtr<CachedMatchedProperties> > Cache;
+    typedef HashMap<AtomicString, RefPtr<StyleSheetContentsCacheItem> > Cache;
     Cache m_cache;
 
-    Timer<MatchedPropertiesCache> m_sweepTimer;
+    Timer<StyleSheetContentsCache> m_sweepTimer;
 };
 
 }