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

test/mjsunit/debug-script-breakpoints.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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --expose-debug-as debug
 // Get the Debug object exposed from the debug context global object.
 Debug = debug.Debug
+Debug.setListener(function(){});
 
 // Set and remove a script break point for a named script.
 var sbp = Debug.setScriptBreakPointByName("1", 2, 3);
 assertEquals(1, Debug.scriptBreakPoints().length);
 assertEquals("1", Debug.scriptBreakPoints()[0].script_name());
 assertEquals(2, Debug.scriptBreakPoints()[0].line());
 assertEquals(3, Debug.scriptBreakPoints()[0].column());
 Debug.clearBreakPoint(sbp);
 assertEquals(0, Debug.scriptBreakPoints().length);
 
@@ skipping 62 matching lines @@
 }
 
 // Remove script break points (in another order than they where added).
 assertEquals(3, Debug.scriptBreakPoints().length);
 Debug.clearBreakPoint(sbp1);
 assertEquals(2, Debug.scriptBreakPoints().length);
 Debug.clearBreakPoint(sbp3);
 assertEquals(1, Debug.scriptBreakPoints().length);
 Debug.clearBreakPoint(sbp2);
 assertEquals(0, Debug.scriptBreakPoints().length);
+
+Debug.setListener(null);