Make root-zone handleUncaughtError rethrow with the correct stack.

runtime/lib/async_patch.dart

Index: runtime/lib/async_patch.dart
diff --git a/runtime/lib/async_patch.dart b/runtime/lib/async_patch.dart
index d78534719656c37ca06fc3cdc7354a930bbeadad..9aabb60a9b661d386c7b47eefa1c02344f243985 100644
--- a/runtime/lib/async_patch.dart
+++ b/runtime/lib/async_patch.dart
@@ -182,3 +182,5 @@ class _AsyncStarStreamController {
     return cancellationCompleter.future;
   }
 }
+
+patch void _rethrow(Object error, StackTrace stackTrace) native "Zone_rethrow";

[Ivan Posva, 2015/10/02 23:40:39]

Strictly speaking this native should be named "Async_rethrow" since it is a
top-level method in the async library and not a method in the Zone class.

Any particular reason why it has to be a top-level method?

[Lasse Reichstein Nielsen, 2015/10/05 06:18:49]

Renamed to Async_rethrow.
It's top-level because it's called from another top-level function. There isn't
any class that it would obviously belong to.
I considered Error, but it's in a different library, so it would have to be
public, and then we would have to implement it in JavaScript too, which isn't
obvious to me how to do (even though having the functionality public would be
awesome!)