Don't propagate synchronous Future.wait errors immediately.

sdk/lib/async/future.dart

Index: sdk/lib/async/future.dart
diff --git a/sdk/lib/async/future.dart b/sdk/lib/async/future.dart
index c64e1c5e0316ca6baa5997c9eb131f6b768bb9bd..7d892c687ef1cd0197b149b65a173d56dcc6f3a5 100644
--- a/sdk/lib/async/future.dart
+++ b/sdk/lib/async/future.dart
@@ -322,8 +322,13 @@ abstract class Future<T> {
       // The error must have been thrown while iterating over the futures
       // list, or while installing a callback handler on the future.
       if (remaining == 0 || eagerError) {
-        // Just complete the error immediately.
-        result._completeError(e, st);
+        // Throw a new Future.error.
+        // Don't just call `result._completeError` since that would propagate
+        // the error too eagerly, not giving the callers time to install
+        // error handlers.
+        // Also, don't use `_asyncCompleteError` since that one doesn't give
+        // zones the chance to intercept the error.
+        return new Future.error(e, st);
       } else {
         // Don't allocate a list for values, thus indicating that there was an
         // error.