Introduce intrinsic to expose debug state to generated code.

src/collection.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 63 matching lines @@
     throw MakeTypeError('incompatible_method_receiver',
                         ['Set.prototype.forEach', this]);
   }
 
   if (!IS_SPEC_FUNCTION(f)) {
     throw MakeTypeError('called_non_callable', [f]);
   }
 
   var iterator = new SetIterator(this, ITERATOR_KIND_VALUES);
   var entry;
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   while (!(entry = %SetIteratorNext(iterator)).done) {
     if (stepping) %DebugPrepareStepInIfStepping(f);
     %_CallFunction(receiver, entry.value, entry.value, this, f);
   }
 }
 
 
 // -------------------------------------------------------------------
 
 function SetUpSet() {
@@ skipping 90 matching lines @@
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.forEach', this]);
   }
 
   if (!IS_SPEC_FUNCTION(f)) {
     throw MakeTypeError('called_non_callable', [f]);
   }
 
   var iterator = new MapIterator(this, ITERATOR_KIND_ENTRIES);
   var entry;
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   while (!(entry = %MapIteratorNext(iterator)).done) {
     if (stepping) %DebugPrepareStepInIfStepping(f);
     %_CallFunction(receiver, entry.value[1], entry.value[0], this, f);
   }
 }
 
 
 // -------------------------------------------------------------------
 
 function SetUpMap() {
@@ skipping 11 matching lines @@
     "get", MapGetJS,
     "set", MapSetJS,
     "has", MapHasJS,
     "delete", MapDeleteJS,
     "clear", MapClearJS,
     "forEach", MapForEach
   ));
 }
 
 SetUpMap();