Changed the debugger API to allow only one debug event listener to be registe...

test/mjsunit/debug-mirror-cache.js

 // Copyright 2008 the V8 project authors. 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 55 matching lines @@
     assertFalse(debug.next_handle_ == 0, "Mirror cache not used");
     assertFalse(debug.mirror_cache_.length == 0, "Mirror cache not used");
   }
   } catch (e) {
     print(e);
     listenerExceptionCount++;
   };
 };
 
 // Add the debug event listener.
-Debug.addListener(listener);
+Debug.setListener(listener);
 
 // Enter the debugger twice.
 debugger;
 debugger;
 
 // Make sure that the debug event listener vas invoked.
 assertEquals(2, listenerCallCount, "Listener not called");
 assertEquals(0, listenerExceptionCount, "Exception in listener");