Pass implementation object to supplemental classes by reference

Source/platform/Supplementable.h

 /*
  * Copyright (C) 2012 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 80 matching lines @@
 class Supplementable;
 
 template<typename T>
 class Supplement {
 public:
     virtual ~Supplement() { }
 #if SECURITY_ASSERT_ENABLED
     virtual bool isRefCountedWrapper() const { return false; }
 #endif
 
-    static void provideTo(Supplementable<T>* host, const char* key, PassOwnPtr<Supplement<T> > supplement)
+    static void provideTo(Supplementable<T>& host, const char* key, PassOwnPtr<Supplement<T> > supplement)
     {
-        host->provideSupplement(key, supplement);
+        host.provideSupplement(key, supplement);
+    }
+
+    static Supplement<T>* from(Supplementable<T>& host, const char* key)
+    {
+        return host.requireSupplement(key);
     }
 
     static Supplement<T>* from(Supplementable<T>* host, const char* key)
     {
         return host ? host->requireSupplement(key) : 0;
     }
 };
 
 template<typename T>
 class Supplementable {
@@ skipping 33 matching lines @@
     typedef HashMap<const char*, OwnPtr<Supplement<T> >, PtrHash<const char*> > SupplementMap;
     SupplementMap m_supplements;
 #if !ASSERT_DISABLED
     ThreadIdentifier m_threadId;
 #endif
 };
 
 } // namespace WebCore
 
 #endif // Supplementable_h