void AppendToString(std::stringstream& aStream, const ScrollMetadata& m, const char* pfx, const char* sfx) { aStream << pfx; AppendToString(aStream, m.GetMetrics(), "{ [metrics=", "]"); if (m.HasClipRect()) { AppendToString(aStream, m.ClipRect(), " [clip=", "]"); } aStream << "}" << sfx; }