The backlog must never delay on-screen work. Urgent jobs (real
Chromium requests) are now stale-dropped too, not just prefetch:
a fast fling queues urgent work for every band it crosses, and all
of it except the final band is dead — it filled the queue cap and
made fresh on-screen requests wait for the JS retry timer.
Safe because the anchor now settles at the final scroll position
(trailing send), and on-screen cells have idx >= VPORT so they can
never be dropped. A pure LIFO would not fix this: stale jobs sit
at the stack bottom, never popped, still blocking the cap.
Emulator fling test: 309 stale urgent jobs purged, queue peak 28,
all 850 decodable images loaded.
Greg Pomerantz
d990627200
