ReportingObserver currently buffers up to 100 reports, removing the oldest once the buffer is full. This could allow for spammy reports to overflow the buffer and clear out other report types entirely, which is not ideal.

The Reporting spec has been updated to allow 100 reports per report type in the buffer, to correct this potential problem:

https://w3c.github.io/reporting/#notify-observers

The implementation of the buffer should be updated to match the spec.