[async await] Fix debug async task event

src/js/async-await.js

Index: src/js/async-await.js
diff --git a/src/js/async-await.js b/src/js/async-await.js
index b733f3d9fa90b81de782ba79d17916d6101b41ea..e7425b33183d92b8796a2000a22a29a420c09910 100644
--- a/src/js/async-await.js
+++ b/src/js/async-await.js
@@ -158,11 +158,16 @@ function AsyncFunctionPromiseRelease(promise) {
   if (DEBUG_IS_ACTIVE) {
     // Cancel
     var id = GET_PRIVATE(promise, promiseAsyncStackIDSymbol);
-    %DebugAsyncTaskEvent({
-      type: "cancel",
-      id: id,
-      name: "async function",
-    });
+
+    // Don't send invalid events when catch prediction is turned on in
+    // the middle of some async operation.
+    if (!IS_UNDEFINED(id)) {
+        %DebugAsyncTaskEvent({

[adamk, 2016/10/14 20:31:12]

Indentation looks off here (should be two spaces).

[gsathya, 2016/10/14 20:47:06]

Done.

+          type: "cancel",
+          id: id,
+          name: "async function",
+        });
+    }
     // Pop the Promise under construction in an async function on
     // from catch prediction stack.
     %DebugPopPromise();