Trigger exception debug event for promises at the throw site.

src/mirror-debugger.js

Index: src/mirror-debugger.js
diff --git a/src/mirror-debugger.js b/src/mirror-debugger.js
index 642bdbc41ae7ae72969b8f33dfe99fd60d4ad727..aff7e19af23623a169c4f33b9a5dfccf7ef76b8e 100644
--- a/src/mirror-debugger.js
+++ b/src/mirror-debugger.js
@@ -1186,7 +1186,7 @@ inherits(PromiseMirror, ObjectMirror);
 
 
 PromiseMirror.prototype.status = function() {
-  var status = %GetPromiseStatus(this.value_);
+  var status = GET_PRIVATE(this.value_, builtins.promiseStatus);
   if (status == 0) return "pending";
   if (status == 1) return "resolved";
   return "rejected";
@@ -1194,7 +1194,7 @@ PromiseMirror.prototype.status = function() {
 
 
 PromiseMirror.prototype.promiseValue = function() {
-  return %GetPromiseValue(this.value_);
+  return GET_PRIVATE(this.value_, builtins.promiseValue);
 };