Remove ListValue::Append(new {Fundamental,String}Value(...)) pattern in //sync

sync/internal_api/js_sync_encryption_handler_observer_unittest.cc

Index: sync/internal_api/js_sync_encryption_handler_observer_unittest.cc
diff --git a/sync/internal_api/js_sync_encryption_handler_observer_unittest.cc b/sync/internal_api/js_sync_encryption_handler_observer_unittest.cc
index 30d9b0053f2ab844d8fc4a2607beb19c20174a72..d8b18a508c72acea0e8586ac677b4562fe6e3167 100644
--- a/sync/internal_api/js_sync_encryption_handler_observer_unittest.cc
+++ b/sync/internal_api/js_sync_encryption_handler_observer_unittest.cc
@@ -119,8 +119,7 @@ TEST_F(JsSyncEncryptionHandlerObserverTest, OnEncryptedTypesChanged) {
   for (int i = FIRST_REAL_MODEL_TYPE; i < MODEL_TYPE_COUNT; ++i) {
     ModelType type = ModelTypeFromInt(i);
     encrypted_types.Put(type);
-    encrypted_type_values->Append(new base::StringValue(
-        ModelTypeToString(type)));
+    encrypted_type_values->AppendString(ModelTypeToString(type));
   }
 
   EXPECT_CALL(mock_js_event_handler_,