[Sync] Add favicon datatype proto support

sync/protocol/proto_enum_conversions.h

 // Copyright 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/base/sync_export.h"
 #include "sync/protocol/client_debug_info.pb.h"
+#include "sync/protocol/favicon_specifics.pb.h"
 #include "sync/protocol/session_specifics.pb.h"
 #include "sync/protocol/sync.pb.h"
 
 // Utility functions to get the string equivalent for some sync proto
 // enums.
 
 namespace syncer {
 
 // The returned strings (which don't have to be freed) are in ASCII.
 // The result of passing in an invalid enum value is undefined.
@@ skipping 19 matching lines @@
 
 SYNC_EXPORT_PRIVATE const char* GetActionString(
     sync_pb::SyncEnums::Action action);
 
 const char* GetDeviceTypeString(
     sync_pb::SyncEnums::DeviceType device_type);
 
 const char* GetFaviconTypeString(
     sync_pb::SessionTab::FaviconType favicon_type);
 
+const char* GetIconTypeString(
+    sync_pb::FaviconData::IconType icon_type);
+
 const char* PassphraseTypeString(
     sync_pb::NigoriSpecifics::PassphraseType type);
 
 const char* SingletonEventTypeString(
     sync_pb::DebugEventInfo::SingletonEventType type);
 
 }  // namespace syncer
 
 #endif  // SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_