[USS] Store supports hosting multiple datatypes per database

components/browser_sync/browser/profile_sync_service.cc

 // Copyright (c) 2012 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 "components/browser_sync/browser/profile_sync_service.h"
 
 #include <stddef.h>
 #include <cstddef>
 #include <map>
 #include <utility>
@@ skipping 281 matching lines @@
           switches::kSyncEnableUSSDeviceInfo)) {
     scoped_refptr<base::SequencedTaskRunner> blocking_task_runner(
         blocking_pool_->GetSequencedTaskRunnerWithShutdownBehavior(
             blocking_pool_->GetSequenceToken(),
             base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
     // TODO(skym): Stop creating leveldb files when signed out.
     // TODO(skym): Verify using AsUTF8Unsafe is okay here. Should work as long
     // as the Local State file is guaranteed to be UTF-8.
     device_info_service_.reset(new DeviceInfoService(
         local_device_.get(),
-        base::Bind(&ModelTypeStore::CreateStore,
+        base::Bind(&ModelTypeStore::CreateStore, syncer::DEVICE_INFO,

[pavely, 2016/06/08 01:18:07]

Optional comment: If PSS performed conversion from ModelType to RootTag here and
passed tag to store it would make store completely oblivious of ModelType
existence (one less dependency).

                    directory_path_.Append(base::FilePath(kLevelDBFolderName))
                        .AsUTF8Unsafe(),
                    blocking_task_runner),
         base::Bind(&SharedModelTypeProcessor::CreateAsChangeProcessor)));
   } else {
     device_info_sync_service_.reset(
         new DeviceInfoSyncService(local_device_.get()));
   }
 
   sync_driver::SyncApiComponentFactory::RegisterDataTypesMethod
@@ skipping 2221 matching lines @@
 }
 
 std::string ProfileSyncService::unrecoverable_error_message() const {
   return unrecoverable_error_message_;
 }
 
 tracked_objects::Location ProfileSyncService::unrecoverable_error_location()
     const {
   return unrecoverable_error_location_;
 }