Debugger: require debugger to be active when dealing with breaks.

test/mjsunit/debug-script.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 18 matching lines @@
 // Flags: --allow-natives-syntax --expose-natives-as natives
 // Flags: --noharmony-shipping
 // Note: this test checks that that the number of scripts reported as native
 // by Debug.scripts() is the same as a number of core native scripts.
 // Native scripts that are added by --harmony-shipping are classified
 // as 'experimental', but are still returned by Debug.scripts(), so
 // we disable harmony-shipping for this test
 
 // Get the Debug object exposed from the debug context global object.
 Debug = debug.Debug;
+Debug.setListener(function(){});
 
 Date();
 RegExp();
 
 // Count script types.
 var named_native_count = 0;
 var named_native_names = {};
 var extension_count = 0;
 var normal_count = 0;
 var scripts = Debug.scripts();
@@ skipping 47 matching lines @@
 }
 
 // Test a normal script.
 var debug_script = Debug.findScript(/debug-script.js/);
 assertTrue(/debug-script.js/.test(debug_script.name));
 assertEquals(Debug.ScriptType.Normal, debug_script.type);
 
 // Check a nonexistent script.
 var dummy_script = Debug.findScript('dummy.js');
 assertTrue(typeof dummy_script == 'undefined');
+
+Debug.setListener(null);