Allow delegate calls even though the target is not reflectable.

sdk/lib/_internal/lib/js_helper.dart

Index: sdk/lib/_internal/lib/js_helper.dart
diff --git a/sdk/lib/_internal/lib/js_helper.dart b/sdk/lib/_internal/lib/js_helper.dart
index 2592a72db5ab0712139849d897bec62e96cb81c3..d4c7fa4ee6b4e7be88e72d69ee40bfd2a424103f 100644
--- a/sdk/lib/_internal/lib/js_helper.dart
+++ b/sdk/lib/_internal/lib/js_helper.dart
@@ -108,10 +108,6 @@ void throwInvalidReflectionError(String memberName) {
       "because it is not included in a @MirrorsUsed annotation.");
 }
 
-bool hasReflectableProperty(var jsFunction) {
-  return JS('bool', '# in #', JS_GET_NAME("REFLECTABLE"), jsFunction);
-}
-
 class JSInvocationMirror implements Invocation {
   static const METHOD = 0;
   static const GETTER = 1;
@@ -217,14 +213,6 @@ class JSInvocationMirror implements Invocation {
       isCatchAll = true;
     }
     if (JS('bool', 'typeof # == "function"', method)) {
-      // TODO(floitsch): bound or tear-off closure does not guarantee that the
-      // function is reflectable.
-      bool isReflectable = hasReflectableProperty(method) ||
-          object is BoundClosure ||
-          object is TearOffClosure;
-      if (!isReflectable) {
-        throwInvalidReflectionError(_symbol_dev.Symbol.getName(memberName));
-      }
       if (isCatchAll) {
         return new CachedCatchAllInvocation(
             name, method, isIntercepted, interceptor);