Fix for regression in content shell tests (see b/36131545)

runtime/lib/function.dart

Index: runtime/lib/function.dart
diff --git a/runtime/lib/function.dart b/runtime/lib/function.dart
index e5308a4884220e38839bf8e3f00cec1db055ef46..0946702a6f278529e1040b488902a5c6694b93d6 100644
--- a/runtime/lib/function.dart
+++ b/runtime/lib/function.dart
@@ -19,7 +19,12 @@ class _Closure implements Function {
   // from C++ code) and also here so that the offset-to-field map used by
   // deferred objects is properly initialized.
   // Caution: These fields are not Dart instances, but VM objects.
-  var instantiator_;
-  var function_;
-  var context_;
+  // The fields had to be renamed here so that they would be private fields
+  // in dart
+  // instantiator_ ===> _instantiator
+  // function_ ===> _function
+  // context_ ===> _context
+  var _instantiator;
+  var _function;
+  var _context;
 }