Move ErrorToString to runtime

src/debug/mirrors.js

 // Copyright 2006-2012 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.
 
 (function(global, utils) {
 "use strict";
 
 // ----------------------------------------------------------------------------
 // Imports
 
-var ErrorToString;
 var GlobalArray = global.Array;
 var IsNaN = global.isNaN;
 var JSONStringify = global.JSON.stringify;
 var MakeError;
 var MapEntries;
 var MapIteratorNext;
 var promiseStateSymbol = utils.ImportNow("promise_state_symbol");
 var promiseResultSymbol = utils.ImportNow("promise_result_symbol");
 var SetIteratorNext;
 var SetValues;
 
 utils.Import(function(from) {
-  ErrorToString = from.ErrorToString;
   MakeError = from.MakeError;
   MapEntries = from.MapEntries;
   MapIteratorNext = from.MapIteratorNext;
   SetIteratorNext = from.SetIteratorNext;
   SetValues = from.SetValues;
 });
 
 // ----------------------------------------------------------------------------
 
 // Mirror hierarchy:
@@ skipping 1213 matching lines @@
  */
 ErrorMirror.prototype.message = function() {
   return this.value_.message;
 };
 
 
 ErrorMirror.prototype.toText = function() {
   // Use the same text representation as in messages.js.
   var text;
   try {
-    text = %_Call(ErrorToString, this.value_);
+    text = %ErrorToString(this.value_);
   } catch (e) {
     text = '#<Error>';
   }
   return text;
 };
 
 
 /**
  * Mirror object for a Promise object.
  * @param {Object} value The Promise object
@@ skipping 1783 matching lines @@
 // Functions needed by the debugger runtime.
 utils.InstallFunctions(utils, DONT_ENUM, [
   "ClearMirrorCache", ClearMirrorCache
 ]);
 
 // Export to debug.js
 utils.Export(function(to) {
   to.MirrorType = MirrorType;
 });
 })