Add synonyms for collection types over MutationObserver-related types.

Source/core/dom/MutationObserver.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 27 matching lines @@
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class Dictionary;
 class ExceptionState;
 class MutationCallback;
+class MutationObserver;
 class MutationObserverRegistration;
 class MutationRecord;
 class Node;
 
 typedef unsigned char MutationObserverOptions;
 typedef unsigned char MutationRecordDeliveryOptions;
 
+typedef WillBeHeapHashSet<RefPtrWillBeMember<MutationObserver> > MutationObserverSet;
+typedef WillBeHeapHashSet<RawPtrWillBeMember<MutationObserverRegistration> > MutationObserverRegistrationSet;
+typedef WillBeHeapVector<RefPtrWillBeMember<MutationObserver> > MutationObserverVector;
+typedef WillBeHeapVector<RefPtrWillBeMember<MutationRecord> > MutationRecordVector;
+
 class MutationObserver FINAL : public RefCountedWillBeGarbageCollectedFinalized<MutationObserver>, public ScriptWrappable {
 public:
     enum MutationType {
         ChildList = 1 << 0,
         Attributes = 1 << 1,
         CharacterData = 1 << 2,
 
         AllMutationTypes = ChildList | Attributes | CharacterData
     };
 
@@ skipping 26 matching lines @@
 
     void trace(Visitor*);
 
 private:
     struct ObserverLessThan;
 
     explicit MutationObserver(PassOwnPtr<MutationCallback>);
     void deliver();
 
     OwnPtr<MutationCallback> m_callback;
-    WillBeHeapVector<RefPtrWillBeMember<MutationRecord> > m_records;
-    WillBeHeapHashSet<RawPtrWillBeMember<MutationObserverRegistration> > m_registrations;
+    MutationRecordVector m_records;
+    MutationObserverRegistrationSet m_registrations;
     unsigned m_priority;
 };
 
 }
 
 #endif // MutationObserver_h