[Sync] Rework Invalidator-related unit tests

sync/notifier/invalidation_util.h

Index: sync/notifier/invalidation_util.h
diff --git a/sync/notifier/invalidation_util.h b/sync/notifier/invalidation_util.h
index 2f3198bc42a63d84ac4220360914dc9544141048..61bd3171d462e23e77ad9e3acd308391ff330b79 100644
--- a/sync/notifier/invalidation_util.h
+++ b/sync/notifier/invalidation_util.h
@@ -11,8 +11,13 @@
 #include <set>
 #include <string>
 
+#include "base/memory/scoped_ptr.h"
 #include "sync/internal_api/public/base/model_type.h"
 
+namespace base {
+class DictionaryValue;
+}  // namespace
+
 namespace invalidation {
 
 class Invalidation;
@@ -38,11 +43,18 @@ bool RealModelTypeToObjectId(ModelType model_type,
 bool ObjectIdToRealModelType(const invalidation::ObjectId& object_id,
                              ModelType* model_type);
 
-ObjectIdSet ModelTypeSetToObjectIdSet(const ModelTypeSet& models);
-ModelTypeSet ObjectIdSetToModelTypeSet(const ObjectIdSet& ids);
+// Caller owns the returned DictionaryValue.
+scoped_ptr<base::DictionaryValue> ObjectIdToValue(
+    const invalidation::ObjectId& object_id);
+
+bool ObjectIdFromValue(const base::DictionaryValue& value,
+                       invalidation::ObjectId* out);
 
 std::string ObjectIdToString(const invalidation::ObjectId& object_id);
 
+ObjectIdSet ModelTypeSetToObjectIdSet(const ModelTypeSet& models);
+ModelTypeSet ObjectIdSetToModelTypeSet(const ObjectIdSet& ids);
+
 std::string InvalidationToString(
     const invalidation::Invalidation& invalidation);