Version: m51
OS: All, presumably

What steps will reproduce the problem?
This was noticed on Google Keep. They have a load spinner that they hide using visibility: hidden that still uses 20-50% of the CPU due to layout and layer tree updates and so on.

What is the expected output?
Non-visible elements should not cause an otherwise static page to use a lot of CPU.

What do you see instead?
Lots of CPU usage that disappear when the visibility: hidden is changed to display: none.

The spinner in question is the standard Material Design spinner. The team want to use visibility to control the display because it can be animated. It seems like we should be able to update the animation without doing layout or going through the effort of repainting the page.

I'll try to generate a small repro.