Log the sync communication that happens between client and server.

sync/protocol/proto_enum_conversions.h

Index: sync/protocol/proto_enum_conversions.h
diff --git a/sync/protocol/proto_enum_conversions.h b/sync/protocol/proto_enum_conversions.h
index fb8d44ba00b8a0b056ca1664d32ce6cb80ebf806..9f397a44a8997d24200472a0d94156e507e355b9 100644
--- a/sync/protocol/proto_enum_conversions.h
+++ b/sync/protocol/proto_enum_conversions.h
@@ -32,6 +32,14 @@ const char* GetPageTransitionQualifierString(
 const char* GetUpdatesSourceString(
     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::ClientToServerResponse::Error::Action action);
+
 const char* GetDeviceTypeString(
     sync_pb::SessionHeader::DeviceType device_type);