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

test/mjsunit/debug-handle.js

 // Copyright 2009 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 156 matching lines @@
 
     // Indicate that all was processed.
     listenerComplete = true;
   }
   } catch (e) {
     exception = e
   };
 };
 
 // Add the debug event listener.
-Debug.addListener(listener);
+Debug.setListener(listener);
 
 function f(a) {
   debugger;
 };
 
 function g(b) {
   f(b);
 };
 
 // Set a break point at return in f and invoke g to hit the breakpoint.
 Debug.setBreakPoint(f, 2, 0);
 o = {};
 p = {}
 o.o = o;
 o.p = p;
 p.o = o;
 p.p = p;
 g(o);
 
 // Make sure that the debug event listener vas invoked.
 assertTrue(listenerComplete, "listener did not run to completion");
 assertFalse(exception, "exception in listener")