Native context: debug.js does not load from js builtins object anymore.

src/runtime.js

 // Copyright 2006-2008 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.
 
 // This files contains runtime support implemented in JavaScript.
 
 // CAUTION: Some of the functions specified in this file are called
 // directly from compiled code. These are the functions with names in
 // ALL CAPS. The compiled code passes the first argument in 'this'.
 
@@ skipping 48 matching lines @@
 var TO_STRING;
 var TO_NAME;
 
 var $defaultNumber;
 var $defaultString;
 var $NaN;
 var $nonNumberToNumber;
 var $nonStringToString;
 var $sameValue;
 var $sameValueZero;
-var $toBoolean;
 var $toInteger;
 var $toLength;
 var $toName;
 var $toNumber;
 var $toPositiveInteger;
 var $toPrimitive;
 var $toString;
 
 (function(global, utils) {
 
@@ skipping 820 matching lines @@
 // Exports
 
 $concatIterableToArray = ConcatIterableToArray;
 $defaultNumber = DefaultNumber;
 $defaultString = DefaultString;
 $NaN = %GetRootNaN();
 $nonNumberToNumber = NonNumberToNumber;
 $nonStringToString = NonStringToString;
 $sameValue = SameValue;
 $sameValueZero = SameValueZero;
-$toBoolean = ToBoolean;
 $toInteger = ToInteger;
 $toLength = ToLength;
 $toName = ToName;
 $toNumber = ToNumber;
 $toPositiveInteger = ToPositiveInteger;
 $toPrimitive = ToPrimitive;
 $toString = ToString;
 
 utils.ExportToRuntime(function(to) {
-  to.ToNumber = $toNumber;
-  to.ToString = $toString;
-  to.ToInteger = $toInteger;
-  to.ToLength = $toLength;
+  to.ToNumber = ToNumber;
+  to.ToString = ToString;
+  to.ToInteger = ToInteger;
+  to.ToLength = ToLength;
 });
 
+utils.Export(function(to) {
+  to.ToBoolean = ToBoolean;
+  to.ToNumber = ToNumber;
+  to.ToString = ToString;
 })
+
+})