title: Chrome DevTools Timeline Update Layer Tree Event
body: <p>I'm building animation/transition heavy web app with a lot of content. There are a lot of composition layers in the app since everything is moved/animated using css transforms. I'm trying to debug the app to find out rendering bottlenecks and I've noticed a lot of "Update Layer Tree" events in  Chrome DevTools -> Timeline -> Frames mode like:
  <img src="https://i.stack.imgur.com/CTGJg.png" alt="enter image description here"> </p>
  
  <p>Does anybody have an idea what could be causing this? What does "Update Layer Tree" exactly stand for?</p>