Rework the format of the FlagList response.

runtime/observatory/lib/src/elements/flag_list.dart

Index: runtime/observatory/lib/src/elements/flag_list.dart
diff --git a/runtime/observatory/lib/src/elements/flag_list.dart b/runtime/observatory/lib/src/elements/flag_list.dart
index b38ad086838fa447f49804f7faaef3c5b849d76b..f2d1cfc4a8ad697b82bc8672f1fad6eb91aa1710 100644
--- a/runtime/observatory/lib/src/elements/flag_list.dart
+++ b/runtime/observatory/lib/src/elements/flag_list.dart
@@ -13,6 +13,16 @@ import 'package:observatory/service.dart';
 class FlagListElement extends ObservatoryElement {
   @published ServiceMap flagList;
 
+  void flagListChanged(oldValue) {
+    modifiedFlags =
+        flagList['flags'].where((flag) => flag['modified']).toList();
+    unmodifiedFlags =
+        flagList['flags'].where((flag) => !flag['modified']).toList();
+  }
+
+  @observable List<ServiceMap> modifiedFlags = new List<ServiceMap>();
+  @observable List<ServiceMap> unmodifiedFlags = new List<ServiceMap>();
+
   FlagListElement.created() : super.created();
 
   Future refresh() {