Implement URLSearchParams.

Source/core/dom/DOMURL.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  * Copyright (C) 2012 Motorola Mobility Inc.
  *
  * 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.
@@ skipping 23 matching lines @@
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class Blob;
 class ExceptionState;
 class ExecutionContext;
 class URLRegistrable;
 
 class DOMURL FINAL : public RefCountedWillBeGarbageCollectedFinalized<DOMURL>, public ScriptWrappable, public DOMURLUtils {
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(DOMURL);
 public:
     static PassRefPtrWillBeRawPtr<DOMURL> create(const String& url, ExceptionState& exceptionState)
     {
         return adoptRefWillBeNoop(new DOMURL(url, blankURL(), exceptionState));
     }
     static PassRefPtrWillBeRawPtr<DOMURL> create(const String& url, const String& base, ExceptionState& exceptionState)
     {
         return adoptRefWillBeNoop(new DOMURL(url, KURL(KURL(), base), exceptionState));
     }
     static PassRefPtrWillBeRawPtr<DOMURL> create(const String& url, PassRefPtrWillBeRawPtr<DOMURL> base, ExceptionState& exceptionState)
     {
         ASSERT(base);
         return adoptRefWillBeNoop(new DOMURL(url, base->m_url, exceptionState));
     }
 
     static String createObjectURL(ExecutionContext*, Blob*, ExceptionState&);
     static void revokeObjectURL(ExecutionContext*, const String&);
 
     static String createPublicURL(ExecutionContext*, URLRegistrable*, const String& uuid = String());
     static void revokeObjectUUID(ExecutionContext*, const String&);
 
     virtual KURL url() const OVERRIDE { return m_url; }
     virtual void setURL(const KURL& url) OVERRIDE { m_url = url; }
 
     virtual String input() const OVERRIDE { return m_input; }
     virtual void setInput(const String&) OVERRIDE;
 
-    void trace(Visitor*) { }
+    virtual void trace(Visitor*) OVERRIDE;
 
 private:
     DOMURL(const String& url, const KURL& base, ExceptionState&);
 
     KURL m_url;
     String m_input;
 };
 
 } // namespace blink
 
 #endif // DOMURL_h