Now that the parent identifies a child process's modules from the section
handle the child sends, and silently skips any handle it cannot identify,
we will need telemetry for how often that skipping happens. This patch
adds counters for that.
unverifiableLoads: the number of module loads in child processes where the DLL
blocklist hook reached the load but failed to duplicate the section handle.
rejectedSections: the number of module section handles a child process sent
to the parent that it refused as invalid module section handles.
The counters are per-process and are only ever incremented for child
processes, so the browser process reports zero for both. The counters are
reported by the process using the module, so their accuracy depends on
trusting the process itself. This is how the UntrustedModulesProcessor
has always worked, and is by design (for performance reasons).
Differential Revision: https://phabricator.services.mozilla.com/D324705
David Parks
b15f195b6f