Add {Map,Set}::FromArray to the API

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.
 
 var $getHash;
 var $getExistingHash;
+var $mapFromArray;
+var $setFromArray;
 
 (function(global, utils) {
 "use strict";
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
 
 var GlobalMap = global.Map;
@@ skipping 456 matching lines @@
   "has", MapHas,
   "delete", MapDelete,
   "clear", MapClearJS,
   "forEach", MapForEach
 ]);
 
 // Expose to the global scope.
 $getHash = GetHash;
 $getExistingHash = GetExistingHash;
 
+$mapFromArray = function(array) {
+  var map = new GlobalMap;
+  var length = array.length;
+  for (var i = 0; i < length; ++i) {
+    var entry = array[i];
+    %_CallFunction(map, entry[0], entry[1], MapSet);
+  }
+  return map;
+};
+
+$setFromArray = function(array) {
+  var set = new GlobalSet;
+  var length = array.length;
+  for (var i = 0; i < length; ++i) {
+    %_CallFunction(set, array[i], SetAdd);
+  }
+  return set;
+};
+
 })