Add tests for stack chains in the browser.

lib/src/chain.dart

Index: lib/src/chain.dart
diff --git a/lib/src/chain.dart b/lib/src/chain.dart
index 3e2100e46340544d87c1e1c1753f892cdda50596..acd17e9d59ea516498fc50ed89b0ecea07290658 100644
--- a/lib/src/chain.dart
+++ b/lib/src/chain.dart
@@ -68,13 +68,6 @@ class Chain implements StackTrace {
   /// considered unhandled.
   ///
   /// If [callback] returns a value, it will be returned by [capture] as well.
-  ///
-  /// Currently, capturing stack chains doesn't work when using dart2js due to
-  /// issues [15171] and [15105]. Stack chains reported on dart2js will contain
-  /// only one trace.
-  ///
-  /// [15171]: https://code.google.com/p/dart/issues/detail?id=15171
-  /// [15105]: https://code.google.com/p/dart/issues/detail?id=15105
   static capture(callback(), {ChainHandler onError}) {
     var spec = new StackZoneSpecification(onError);
     return runZoned(() {