Store CompositeTile instances in local space, and add support for compositor
transforms that can map local -> raster -> device space without access to the
spatial tree.

This is prep work for supporting picture cache tiles that are scaled by the
composite step during pinch-zoom, for low-end GPUs. Follow up patches will
port the native compositor surface and external descriptors to also work
in local space, converting to raster or device space on demand as required.

Backed out along with Bug 1711648 as it was causing backout conflicts.

Please see https://bugzilla.mozilla.org/show_bug.cgi?id=1711648#c15

This patch was backed out due to causing merge conflicts when backing out an earlier patch. Trying to re-land this patch now without changes, since the preceding patch has been fixed and re-landed.

Backed out changeset 7ce1b7de9a7c (bug 1713544) for causing wrench bustages.
https://hg.mozilla.org/integration/autoland/rev/9ecdea1ab1382c13c34906782de6cd9a522cb694

Push with failures:
https://treeherder.mozilla.org/jobs?repo=autoland&revision=7ce1b7de9a7c3a9bba387e2f6ac1c1e64f2e977c&selectedTaskRun=f_ShajEVTueEvhWY3M2c0w.0

Failure log:
https://treeherder.mozilla.org/logviewer?job_id=341564500&repo=autoland&lineNumber=33650

The failure is that it fails to decode an updated PNG file. However, the wrench jobs pass just fine and are all green on my local machine, and also on a try run (https://treeherder.mozilla.org/jobs?repo=try&revision=ca14f1fd88a0ab9c4e14413818b4d6b05f451e9f).

I'm going to try re-land the patch as-is, to see if it's some kind of intermittent CI flakiness.

If not, there might be some image file corruption going on somewhere between phabricator -> lando -> autoland perhaps?

https://hg.mozilla.org/mozilla-central/rev/5452bb0b5363

There is a bisected regression for this (https://bugzilla.mozilla.org/show_bug.cgi?id=1714487). I probably won't be able to look into it until Monday. If it's rare it can probably wait until then. If it's more urgent than that, please feel free to back it out over the weekend.

Backed out as requested: https://hg.mozilla.org/integration/autoland/rev/d29c9762882dda4efd6e1e9ffe8f53eb0bedfc8c

Updated the patch to correct the regressions in #1714502 and #1714487.

https://hg.mozilla.org/mozilla-central/rev/c4878547fc48