It would be great to get memory-metric alerts for the WebWorker story of the memory_desktop benchmark to catch regressions.

The most important metrics are:
- memory:chrome:renderer_processes:reported_by_os:private_footprint_size
- memory:chrome:renderer_processes:reported_by_os:resident_size_avg
- memory:chrome:renderer_processes:reported_by_chrome:effective_size

Other memory metrics would be also useful.

The alerts to go to the general perf rotation.