1This empty folder exists to harmonize "built-in" metrics 2work with the "metric extension" functionality of trace processor. 3 4Essentially by adding a protos folder, we can pass 5src/trace_processor/metrics as an extension path to shell to 6override all built-in metrics. This means we can change the SQL 7files *without* needing to recompile trace processor. 8 9In the future, we might also move the protos here but that would 10be a bigger change which would need coordination across repos ( 11e.g. Chrome because of the metrics autoroller for Chrome metrics). 12