Backport analyzer-experimental changes to 'resources'.

R=devoncarew@google.com
BUG=

Review URL: https://codereview.chromium.org//13884016

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@21385 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/pkg/analyzer_experimental/lib/src/generated/java_core.dart b/pkg/analyzer_experimental/lib/src/generated/java_core.dart
index f293998..995fa42 100644
--- a/pkg/analyzer_experimental/lib/src/generated/java_core.dart
+++ b/pkg/analyzer_experimental/lib/src/generated/java_core.dart
@@ -375,7 +375,7 @@
       _coPos--;
       (_iterable as List).remove(_coPos);
     } else if (_iterable is Set) {
-      _iterable.remove(_current);
+      (_iterable as Set).remove(_current);
     } else {
       throw new StateError("Unsupported iterable ${_iterable.runtimeType}");
     }