Add v8::Promise::Then.

src/promise.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 $Object = global.Object
 // var $WeakMap = global.WeakMap
 
 // For bootstrapper.
 
 var IsPromise;
 var PromiseCreate;
 var PromiseResolve;
 var PromiseReject;
 var PromiseChain;
 var PromiseCatch;
+var PromiseThen;
 
 // mirror-debugger.js currently uses builtins.promiseStatus. It would be nice
 // if we could move these property names into the closure below.
 // TODO(jkummerow/rossberg/yangguo): Find a better solution.
 
 // Status values: 0 = pending, +1 = resolved, -1 = rejected
 var promiseStatus = GLOBAL_PRIVATE("Promise#status");
 var promiseValue = GLOBAL_PRIVATE("Promise#value");
 var promiseOnResolve = GLOBAL_PRIVATE("Promise#onResolve");
 var promiseOnReject = GLOBAL_PRIVATE("Promise#onReject");
@@ skipping 183 matching lines @@
     }
     return deferred.promise;
   }
 
   PromiseCatch = function PromiseCatch(onReject) {
     return this.then(UNDEFINED, onReject);
   }
 
   // Multi-unwrapped chaining with thenable coercion.
 
-  function PromiseThen(onResolve, onReject) {
+  PromiseThen = function PromiseThen(onResolve, onReject) {
     onResolve = IS_SPEC_FUNCTION(onResolve) ? onResolve
                                             : PromiseIdResolveHandler;
     onReject = IS_SPEC_FUNCTION(onReject) ? onReject
                                           : PromiseIdRejectHandler;
     var that = this;
     var constructor = this.constructor;
     return %_CallFunction(
       this,
       function(x) {
         x = PromiseCoerce(constructor, x);
@@ skipping 73 matching lines @@
     "race", PromiseOne,
     "resolve", PromiseCast
   ]);
   InstallFunctions($Promise.prototype, DONT_ENUM, [
     "chain", PromiseChain,
     "then", PromiseThen,
     "catch", PromiseCatch
   ]);
 
 })();