[debugger] remove step count parameter from prepare step.

test/mjsunit/debug-step.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 19 matching lines @@
 Debug = debug.Debug
 
 // Simple debug event handler which first time hit will perform 1000 steps and
 // second time hit will evaluate and store the value of "i". If requires that
 // the global property "state" is initially zero.
 
 var bp1, bp2;
 
 function listener(event, exec_state, event_data, data) {
   if (event == Debug.DebugEvent.Break) {
-    if (state == 0) {
-      exec_state.prepareStep(Debug.StepAction.StepIn, 1000);
-      state = 1;
-    } else if (state == 1) {
+    if (step_count > 0) {
+      exec_state.prepareStep(Debug.StepAction.StepIn);
+      step_count--;
+    } else {
       result = exec_state.frame().evaluate("i").value();
       // Clear the break point on line 2 if set.
       if (bp2) {
         Debug.clearBreakPoint(bp2);
       }
     }
   }
 };
 
 // Add the debug event listener.
 Debug.setListener(listener);
 
 // Test debug event for break point.
 function f() {
   var i;                        // Line 1.
   for (i = 0; i < 1000; i++) {  // Line 2.
     x = 1;                      // Line 3.
   }
 };
 
 // Set a breakpoint on the for statement (line 1).
 bp1 = Debug.setBreakPoint(f, 1);
 
 // Check that performing 1000 steps will make i 499.
-state = 0;
+var step_count = 1000;
 result = -1;
 f();
 assertEquals(332, result);
-
-// Check that performing 1000 steps with a break point on the statement in the
-// for loop (line 2) will only make i 0 as a real break point breaks even when
-// multiple steps have been requested.
-state = 0;
-result = -1;
-bp2 = Debug.setBreakPoint(f, 3);
-f();
-assertEquals(0, result);
-
-// Get rid of the debug event listener.
 Debug.setListener(null);