Retain types of toplevel and instance variables for reflection.

sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
index a5db634e9c448e16c87cff67f4672b055658016d..6c613f8f9f9b176118ef58d820d0b776ac7cb6c6 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
@@ -212,7 +212,11 @@ class ClassEmitter extends CodeEmitterHelper {
             }
           }
           if (backend.isAccessibleByReflection(field)) {
-            buffer.write(new String.fromCharCode(REFLECTION_MARKER));
+            buffer.write(':');
+            if (backend.isNeededForReflection(field)) {
+              DartType type = field.computeType(compiler);
+              buffer.write('${task.metadataEmitter.reifyType(type)}');
+            }
           }
         }
       });