Don't use magic strings/properties to communicate between compiler and runtime.

pkg/compiler/lib/src/js_emitter/class_stub_generator.dart

Index: pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
index 1388ba868ad1e9b1d7749d6e56d7edd3d70c439a..5f40300504b208af7cedc70a4d8a8a0041b8bf9d 100644
--- a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
@@ -40,8 +40,9 @@ class ClassStubGenerator {
     var typeParameters = const <jsAst.Parameter>[];
     var typeInits = const <jsAst.Expression>[];
     if (hasRtiField) {
-      typeParameters = namer.rtiFieldName;
-      typeInits = js('this.# = #', [namer.rtiFieldName, namer.rtiFieldName]);
+      var rtiName = namer.rtiFieldJsName;
+      typeParameters = rtiName
+      typeInits = js('this.# = #', [rtiName, rtiName]);
     }
     return js('function(#, #) { #; #; this.#();}', [
       fields,