Subscribe to memory pressure events on macOS and add crash report annotations to parent and content process crash reports that can be used to determine if the system was under memory pressure at the time of the crash.
Include the memory pressure level reported via the DISPATCH_SOURCE_TYPE_MEMORYPRESSURE dispatch with timestamps of transitions, the memory pressure level as read from the kern.memorystatus_vm_pressure_level sysctl, and a measurement of the percentage of available memory in the system read from the kern.memorystatus_level sysctl.
Differential Revision: https://phabricator.services.mozilla.com/D116725
66b55bf012