Enable Null Syncable ID which is different than Root ID.

sync/engine/syncer_util_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/engine/syncer_util.h"
 
 #include "base/rand_util.h"
 #include "sync/internal_api/public/base/unique_position.h"
 #include "sync/internal_api/public/test/test_entry_factory.h"
 #include "sync/protocol/sync.pb.h"
@@ skipping 145 matching lines @@
   return result;
 }
 
 }  // namespace
 
 // Checks that whole cycle of unique_position updating from
 // server works fine and does not browser crash.
 TEST_F(GetUpdatePositionTest, UpdateServerFieldsFromUpdateTest) {
   InitSuffixIngredients();  // Initialize update with valid data.
 
-  std::string root_server_id = syncable::GetNullId().GetServerId();
+  std::string root_server_id = syncable::Id::GetRoot().GetServerId();
   int64 handle = entry_factory()->CreateUnappliedNewBookmarkItemWithParent(
       "I", DefaultBookmarkSpecifics(), root_server_id);
 
   syncable::WriteTransaction trans(FROM_HERE, syncable::UNITTEST, directory());
   syncable::MutableEntry target(&trans, syncable::GET_BY_HANDLE, handle);
 
   // Before update, target has invalid bookmark tag and unique position.
   EXPECT_FALSE(UniquePosition::IsValidSuffix(target.GetUniqueBookmarkTag()));
   EXPECT_FALSE(target.GetServerUniquePosition().IsValid());
   UpdateServerFieldsFromUpdate(&target, update, "name");
 
   // After update, target has valid bookmark tag and unique position.
   EXPECT_TRUE(UniquePosition::IsValidSuffix(target.GetUniqueBookmarkTag()));
   EXPECT_TRUE(target.GetServerUniquePosition().IsValid());
 }
 
 // Checks that whole cycle of unique_position updating does not
 // browser crash even data from server is invalid.
 // It looks like server bug, but browser should not crash and work further.
 TEST_F(GetUpdatePositionTest, UpdateServerFieldsFromInvalidUpdateTest) {
   // Do not initialize data in update, update is invalid.
 
-  std::string root_server_id = syncable::GetNullId().GetServerId();
+  std::string root_server_id = syncable::Id::GetRoot().GetServerId();
   int64 handle = entry_factory()->CreateUnappliedNewBookmarkItemWithParent(
       "I", DefaultBookmarkSpecifics(), root_server_id);
 
   syncable::WriteTransaction trans(FROM_HERE, syncable::UNITTEST, directory());
   syncable::MutableEntry target(&trans, syncable::GET_BY_HANDLE, handle);
 
   // Before update, target has invalid bookmark tag and unique position.
   EXPECT_FALSE(UniquePosition::IsValidSuffix(target.GetUniqueBookmarkTag()));
   EXPECT_FALSE(target.GetServerUniquePosition().IsValid());
   UpdateServerFieldsFromUpdate(&target, update, "name");
 
   // After update, target has valid bookmark tag and unique position.
   EXPECT_TRUE(UniquePosition::IsValidSuffix(target.GetUniqueBookmarkTag()));
   EXPECT_TRUE(target.GetServerUniquePosition().IsValid());
 }
 
 }  // namespace syncer