Revert "Simplify DocumentOrderedMap"

Source/core/dom/DocumentOrderedMap.h

Index: Source/core/dom/DocumentOrderedMap.h
diff --git a/Source/core/dom/DocumentOrderedMap.h b/Source/core/dom/DocumentOrderedMap.h
index a86caf0e66f562a0735669e0a7104661e19f778d..b6fc8e07e0df1e0111506225fd0bc5c4bd1e0cc8 100644
--- a/Source/core/dom/DocumentOrderedMap.h
+++ b/Source/core/dom/DocumentOrderedMap.h
@@ -33,7 +33,6 @@
 
 #include "wtf/HashCountedSet.h"
 #include "wtf/HashMap.h"
-#include "wtf/Vector.h"
 #include "wtf/text/StringImpl.h"
 
 namespace WebCore {
@@ -48,60 +47,35 @@ public:
     void clear();
 
     bool contains(StringImpl*) const;
-    bool containsSingle(StringImpl*) const;
     bool containsMultiple(StringImpl*) const;
-
     // concrete instantiations of the get<>() method template
     Element* getElementById(StringImpl*, const TreeScope*) const;
-    Element* getElementByName(StringImpl*, const TreeScope*) const;
     Element* getElementByMapName(StringImpl*, const TreeScope*) const;
     Element* getElementByLowercasedMapName(StringImpl*, const TreeScope*) const;
     Element* getElementByLabelForAttribute(StringImpl*, const TreeScope*) const;
 
-    const Vector<Element*>* getAllElementsById(StringImpl*, const TreeScope*) const;
-
     void checkConsistency() const;
 
 private:
     template<bool keyMatches(StringImpl*, Element*)> Element* get(StringImpl*, const TreeScope*) const;
 
-    struct MapEntry {
-        MapEntry()
-            : element(0)
-            , count(0)
-        {
-        }
-        explicit MapEntry(Element* firstElement)
-            : element(firstElement)
-            , count(1)
-        {
-        }
-
-        Element* element;
-        unsigned count;
-        Vector<Element*> orderedList;
-    };
-
-    typedef HashMap<StringImpl*, MapEntry> Map;
+    typedef HashMap<StringImpl*, Element*> Map;
 
+    // We maintain the invariant that m_duplicateCounts is the count of all elements with a given key
+    // excluding the one referenced in m_map, if any. This means it one less than the total count
+    // when the first node with a given key is cached, otherwise the same as the total count.
     mutable Map m_map;
+    mutable HashCountedSet<StringImpl*> m_duplicateCounts;
 };
 
-inline bool DocumentOrderedMap::containsSingle(StringImpl* id) const
-{
-    Map::const_iterator it = m_map.find(id);
-    return it != m_map.end() && it->value.count == 1;
-}
-
 inline bool DocumentOrderedMap::contains(StringImpl* id) const
 {
-    return m_map.contains(id);
+    return m_map.contains(id) || m_duplicateCounts.contains(id);
 }
 
 inline bool DocumentOrderedMap::containsMultiple(StringImpl* id) const
 {
-    Map::const_iterator it = m_map.find(id);
-    return it != m_map.end() && it->value.count > 1;
+    return m_duplicateCounts.contains(id);
 }
 
 } // namespace WebCore