sync: Add DeviceInfo protobuf and supporting code

sync/protocol/proto_enum_conversions.h

 // 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.
 
 #ifndef SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_
 #define SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_
 
 // Keep this file in sync with the .proto files in this directory.
 
 #include "sync/protocol/session_specifics.pb.h"
@@ skipping 21 matching lines @@
     sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source);
 
 const char* GetResponseTypeString(
     sync_pb::CommitResponse::ResponseType response_type);
 
 const char* GetErrorTypeString(sync_pb::SyncEnums::ErrorType error_type);
 
 const char* GetActionString(sync_pb::SyncEnums::Action action);
 
 const char* GetDeviceTypeString(
-    sync_pb::SessionHeader::DeviceType device_type);
+    sync_pb::SyncEnums::DeviceType device_type);
 
 const char* GetFaviconTypeString(
     sync_pb::SessionTab::FaviconType favicon_type);
 
 const char* PassphraseTypeString(
     sync_pb::NigoriSpecifics::PassphraseType type);
 
 }  // namespace syncer
 
 #endif  // SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_