[stubs] Unify (and optimize) implementation of ToObject.

src/harmony-object.js

 // Copyright 2014 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";
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
 
 var GlobalObject = global.Object;
 
 var OwnPropertyKeys;
 
 utils.Import(function(from) {
   OwnPropertyKeys = from.OwnPropertyKeys;
 });
 
 // -------------------------------------------------------------------
 
 // ES6, draft 04-03-15, section 19.1.2.1
 function ObjectAssign(target, sources) {
-  var to = TO_OBJECT_INLINE(target);
+  var to = TO_OBJECT(target);
   var argsLen = %_ArgumentsLength();
   if (argsLen < 2) return to;
 
   for (var i = 1; i < argsLen; ++i) {
     var nextSource = %_Arguments(i);
     if (IS_NULL_OR_UNDEFINED(nextSource)) {
       continue;
     }
 
-    var from = TO_OBJECT_INLINE(nextSource);
+    var from = TO_OBJECT(nextSource);
     var keys = OwnPropertyKeys(from);
     var len = keys.length;
 
     for (var j = 0; j < len; ++j) {
       var key = keys[j];
       if (%IsPropertyEnumerable(from, key)) {
         var propValue = from[key];
         to[key] = propValue;
       }
     }
   }
   return to;
 }
 
 // Set up non-enumerable functions on the Object object.
 utils.InstallFunctions(GlobalObject, DONT_ENUM, [
   "assign", ObjectAssign
 ]);
 
 })