Introduce TerminatedArray<T> type to make data-structure used by RuleSet visible at the type level.

Source/core/css/RuleSet.h

Index: Source/core/css/RuleSet.h
diff --git a/Source/core/css/RuleSet.h b/Source/core/css/RuleSet.h
index 8b259bd506f9aa49bbb8eb97a5f5b349cc5ac54d..947151a837e97a94badf7a30190c41b85146c762 100644
--- a/Source/core/css/RuleSet.h
+++ b/Source/core/css/RuleSet.h
@@ -30,6 +30,7 @@
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/LinkedStack.h"
+#include "wtf/TerminatedArray.h"
 
 namespace WebCore {
 
@@ -125,10 +126,10 @@ public:
 
     const RuleFeatureSet& features() const { return m_features; }
 
-    const RuleData* idRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
-    const RuleData* classRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
-    const RuleData* tagRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
-    const RuleData* shadowPseudoElementRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }
+    const TerminatedArray<RuleData>* idRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
+    const TerminatedArray<RuleData>* classRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
+    const TerminatedArray<RuleData>* tagRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
+    const TerminatedArray<RuleData>* shadowPseudoElementRules(const AtomicString& key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }
     const Vector<RuleData>* linkPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_linkPseudoClassRules; }
     const Vector<RuleData>* cuePseudoRules() const { ASSERT(!m_pendingRules); return &m_cuePseudoRules; }
     const Vector<RuleData>* focusPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_focusPseudoClassRules; }
@@ -164,7 +165,7 @@ public:
 
 private:
     typedef HashMap<AtomicString, OwnPtr<LinkedStack<RuleData> > > PendingRuleMap;
-    typedef HashMap<AtomicString, OwnPtr<RuleData> > CompactRuleMap;
+    typedef HashMap<AtomicString, OwnPtr<TerminatedArray<RuleData> > > CompactRuleMap;
 
     RuleSet()
         : m_ruleCount(0)