Add fast path for tag#id selector queries

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 fa1e39d573fab7e50cf2331cce3541d2ea179892..d1a9c2f075c07e42cafef5a8c421675867a312b9 100644
--- a/Source/core/dom/DocumentOrderedMap.h
+++ b/Source/core/dom/DocumentOrderedMap.h
@@ -33,6 +33,7 @@
 
 #include "wtf/HashCountedSet.h"
 #include "wtf/HashMap.h"
+#include "wtf/Vector.h"
 #include "wtf/text/StringImpl.h"
 
 namespace WebCore {
@@ -50,6 +51,7 @@ public:
     bool containsMultiple(StringImpl*) const;
     // concrete instantiations of the get<>() method template
     Element* getElementById(StringImpl*, const TreeScope*) const;
+    const Vector<Element*>& getAllElementsById(StringImpl*, const TreeScope*) const;
     Element* getElementByMapName(StringImpl*, const TreeScope*) const;
     Element* getElementByLowercasedMapName(StringImpl*, const TreeScope*) const;
     Element* getElementByLabelForAttribute(StringImpl*, const TreeScope*) const;
@@ -72,6 +74,7 @@ private:
 
         Element* element;
         unsigned count;
+        Vector<Element*> orderedList;
     };
 
     typedef HashMap<StringImpl*, MapEntry> Map;