There's two totally different places where we emit this metric.  base/memory/memory_pressure_monitor.cc and components/memory_pressure/memory_pressure_stats_collector.cc. 

In the former [MemoryPressureMonitor::RecordMemoryPressure], we add 1-bucket count per 5 seconds that have passed since we last called this method. Looking to see when this method gets called...which only happens in RendererFrameManager::GetMaxNumberOfSavedFrames, and only if memory coordinator experiment is turned off. Okay...

The latter [MemoryPressureStatsCollector::ReportCumulativeTime] adds 1-bucket count per 1 second that has not yet been recorded. But...this requires MEMORY_PRESSURE_IS_POLLING to be defined, which currently isn't for macOS.

Given that the semantics have changed [1 -> 5 seconds], and these metrics get emitted in different circumstances [!memory coordinator for former], can we just emit two different UMA graphs?