[Sync] Rework Invalidator-related unit tests

sync/notifier/object_id_state_map.h

Index: sync/notifier/object_id_state_map.h
diff --git a/sync/notifier/object_id_state_map.h b/sync/notifier/object_id_state_map.h
index 17f8cebe686fc31b35e9cc35b7075b479c38ffba..87f3694ed61ed2067007f4f6a6cb4861fc9f6769 100644
--- a/sync/notifier/object_id_state_map.h
+++ b/sync/notifier/object_id_state_map.h
@@ -13,6 +13,10 @@
 #include "sync/internal_api/public/base/model_type_state_map.h"
 #include "sync/notifier/invalidation_util.h"
 
+namespace base {
+class ListValue;
+}  // namespace base
+
 namespace syncer {
 
 typedef std::map<invalidation::ObjectId,
@@ -24,6 +28,16 @@ ObjectIdSet ObjectIdStateMapToSet(const ObjectIdStateMap& id_payloads);
 ObjectIdStateMap ObjectIdSetToStateMap(const ObjectIdSet& ids,
                                        const std::string& payload);
 
+bool ObjectIdStateMapEquals(const ObjectIdStateMap& id_state_map1,
+                            const ObjectIdStateMap& id_state_map2);
+
+// Caller takes ownership of the returned dictionary.
+base::ListValue* ObjectIdStateMapToValue(
+    const ObjectIdStateMap& model_type_payloads);
+
+bool ObjectIdStateMapFromValue(const base::ListValue& value,
+                               ObjectIdStateMap* out);
+
 // Converts between ObjectIdStateMaps and ModelTypeStateMaps.
 ModelTypeStateMap ObjectIdStateMapToModelTypeStateMap(
     const ObjectIdStateMap& id_payloads);