All freezable task queues (beyond timers and loading) in blink scheduler will be frozen when a renderer has been in the background after a grace time of 5 minutes on Android. Many sites continue activity, even after their app has been in background for over 5 minutes. This consumes non-trivial amount of CPU and network bandwidth, and hurts the responsiveness of the foreground app, especially on mobile. This intervention completes freezing background work on mobile.
Docs: https://docs.google.com/document/d/10D2uvOVxBZ2YhcwtK1XOb6CClminPpqAeS82KOVT7hk/edit# https://wicg.github.io/page-lifecycle/spec.html