Generate tear-off closures dynamically.

dart/sdk/lib/_internal/lib/isolate_helper.dart

Index: dart/sdk/lib/_internal/lib/isolate_helper.dart
diff --git a/dart/sdk/lib/_internal/lib/isolate_helper.dart b/dart/sdk/lib/_internal/lib/isolate_helper.dart
index 474d6af8c7727dbf0db6163a2e22add8ddec6601..1da84ba4f48f6fb23f0e42313965ff00e3576136 100644
--- a/dart/sdk/lib/_internal/lib/isolate_helper.dart
+++ b/dart/sdk/lib/_internal/lib/isolate_helper.dart
@@ -8,6 +8,7 @@ import 'dart:async';
 import 'dart:collection' show Queue, HashMap;
 import 'dart:isolate';
 import 'dart:_js_helper' show
+    Closure,
     Null,
     Primitives,
     convertDartClosureToJS;
@@ -548,7 +549,7 @@ class IsolateNatives {
   }
 
   static _getJSFunctionFromName(String functionName) {
-    return JS("", "init.globalFunctions[#]", functionName);
+    return JS("", "init.globalFunctions[#]()", functionName);
   }
 
   /**
@@ -557,7 +558,8 @@ class IsolateNatives {
    * but you should probably not count on this.
    */
   static String _getJSFunctionName(Function f) {
-    return JS("String|Null", r"(#['$name'] || #)", f, null);
+    if (f is! Closure) return null;
+    return JS("String|Null", r'#.$name', f);
   }
 
   /** Create a new JavaScript object instance given its constructor. */