Add markPromiseAsHandled V8 extra util

src/js/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.
 
 (function(global, utils, extrasUtils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 569 matching lines @@
 
 // Return whether the promise will be handled by a user-defined reject
 // handler somewhere down the promise chain. For this, we do a depth-first
 // search for a reject handler that's not the default PromiseIdRejectHandler.
 // This function also traverses dependencies of one Promise on another,
 // set up through async/await and Promises resolved with Promises.
 function PromiseHasUserDefinedRejectHandler() {
   return PromiseHasUserDefinedRejectHandlerRecursive(this);
 };
 
+function MarkPromiseAsHandled(promise) {
+  SET_PRIVATE(promise, promiseHasHandlerSymbol, true);
+}

[Dan Ehrenberg, 2016/11/15 10:34:39]

I like factoring this out into a separate function. It'd be great to do a quick
find/replace of this line to make it call out to this function, but understand
if you want to leave that refactoring for a later patch.

+
 
 function PromiseSpecies() {
   return this;
 }
 
 // -------------------------------------------------------------------
 // Install exported functions.
 
 %AddNamedProperty(global, 'Promise', GlobalPromise, DONT_ENUM);
 %AddNamedProperty(GlobalPromise.prototype, toStringTagSymbol, "Promise",
@@ skipping 25 matching lines @@
   "promise_handle", PromiseHandle,
   "promise_debug_get_info", PromiseDebugGetInfo
 ]);
 
 // This allows extras to create promises quickly without building extra
 // resolve/reject closures, and allows them to later resolve and reject any
 // promise without having to hold on to those closures forever.
 utils.InstallFunctions(extrasUtils, 0, [
   "createPromise", PromiseCreate,
   "resolvePromise", ResolvePromise,
-  "rejectPromise", DoRejectPromise
+  "rejectPromise", DoRejectPromise,
+  "markPromiseAsHandled", MarkPromiseAsHandled

[Dan Ehrenberg, 2016/11/15 10:35:14]

Maybe add a trailing comma here so that future patches don't have to touch
earlier unaffected lines.

 ]);
 
 utils.Export(function(to) {
   to.IsPromise = IsPromise;
   to.PromiseCreate = PromiseCreate;
   to.PromiseThen = PromiseThen;
 
   to.GlobalPromise = GlobalPromise;
   to.NewPromiseCapability = NewPromiseCapability;
   to.PerformPromiseThen = PerformPromiseThen;
   to.ResolvePromise = ResolvePromise;
   to.RejectPromise = RejectPromise;
 });
 
 })