Running https://jrmuizel.github.io/perf-tests/motion-mark-tagged-images-still.html gives a display list like: http://jrmuizel.github.io/bugs/frame-6.yaml. In the child pipeline you'll notice that we have a bunch of unneeded duplicate clips like: - bounds: [81.5, 136, 1600, 800] "clip-rect": [81.5, 136, 1600, 800] "clip-and-scroll": 2 type: clip id: 38 "content-size": [1600, 800] Removing them didn't improve performance but it will keep our display lists smaller and reduce processing time on the child and parent. (I did notice clip pushing time in child showing up in profiles in child)

I'm duping this against 1450701 as that's more current.

That should've been bug 1485420