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

test/mjsunit/debug-stepin-constructor.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 27 matching lines @@
     if (exec_state.frameCount() > 1) {
       exec_state.prepareStep(Debug.StepAction.StepIn);
     }
     
     // Test that there is a script.
     assertTrue(typeof(event_data.func().script()) == 'object');
   }
 };
 
 // Add the debug event listener.
-Debug.addListener(listener);
+Debug.setListener(listener);
 
 // Test step into constructor with simple constructor.
 function X() {
 }
 
 function f() {
   debugger;
   new X();
 };
 
 break_break_point_hit_count = 0;
 f();
 assertEquals(5, break_break_point_hit_count);
 
 // Test step into constructor with builtin constructor.
 function g() {
   debugger;
   new Date();
 };
 
 break_break_point_hit_count = 0;
 g();
 assertEquals(4, break_break_point_hit_count);
 
 // Get rid of the debug event listener.
-Debug.removeListener(listener);
+Debug.setListener(null);