Zooming text on webrender on android is slow again. If you enable gfx.webrender.debug.texture-cache you can see the cache growing ridiculously massive after the slightest zoom, so the fix from bug 1531142 seems to have been regressed.

Mozregression points to bug 1558106.

I'm a bit concerned this has taken me a month to catch, my pixel 2 is just about fast enough and I zoom infrequently enough that I didn't notice. But it's terrible on the Moto g5 for example. I'm not sure how we can automatically test for this, hopefully performance tests will be enough once we have them up and running.

I'm concerned as well. I'm also not sure our current performance tests would have caught this because I don't think we have any performance tests for async zoom. I filed bug 1566083 about getting something.

Thankfully this isn't as bad as I feared, I had accidentally disabled picture caching. This has only regressed when picture caching is disabled, it still works as expected with picture caching enabled. So this might still be nice to fix but isn't a blocker.

I believe this has been fixed by bug 1661135, which I think makes sense - we were using the picture's spatial node to detect zooming rather than the primitive's. If picture caching is disabled, then the picture's spatial node will be the root spatial node, so it never thinks we are zooming.

Closing this as a dup.