Add UseCounters for various standards-related code paths

src/js/promise.js

Index: src/js/promise.js
diff --git a/src/js/promise.js b/src/js/promise.js
index 6fc8728562c03f4e5def5bc4d3dcc72088b90b75..131021c979240f8f680661a6a2e0e252ccf65b27 100644
--- a/src/js/promise.js
+++ b/src/js/promise.js
@@ -24,6 +24,9 @@ var promiseRawSymbol = utils.ImportNow("promise_raw_symbol");
 var promiseStatusSymbol = utils.ImportNow("promise_status_symbol");
 var promiseValueSymbol = utils.ImportNow("promise_value_symbol");
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
+const kPromiseChain = 17;
+const kPromiseAccept = 18;
+const kPromiseDefer = 19;

[adamk, 2016/01/05 19:10:09]

Same for theses consts. I can imagine doing a cleanup later where we move
constants from macros into the source file.

I'm open to arguments for why we should diverge here.

[Dan Ehrenberg, 2016/01/06 03:20:55]

I don't like macros! But this patch isn't the forum for that kind of argument.
Switched to using macros.

 
 utils.Import(function(from) {
   MakeTypeError = from.MakeTypeError;
@@ -239,10 +242,12 @@ function NewPromiseCapability(C) {
 }
 
 function PromiseDeferred() {

[adamk, 2016/01/05 19:10:09]

Could this be renamed "PromiseDefer" for clarity? It looks like it doesn't
really have callers any more.

[Dan Ehrenberg, 2016/01/06 03:20:55]

Agreed that this is confusing. I plan to do this and other cleanups that Camillo
recommended once the current batch of Promise patches goes in (chiefly Caitlin's
patches).

+  %IncrementUseCounter(kPromiseDefer);
   return NewPromiseCapability(this);
 }
 
 function PromiseResolved(x) {

[adamk, 2016/01/05 19:10:09]

Same here, clarity. The two lines where this function has different names are
surprising.

[Dan Ehrenberg, 2016/01/06 03:20:55]

Ditto.

+  %IncrementUseCounter(kPromiseAccept);
   return %_Call(PromiseCast, this, x);
 }
 
@@ -306,6 +311,7 @@ function PromiseThen(onResolve, onReject) {
 
 // Chain is left around for now as an alias for then
 function PromiseChain(onResolve, onReject) {
+  %IncrementUseCounter(kPromiseChain);
   return %_Call(PromiseThen, this, onResolve, onReject);
 }