- Reuse DOM nodes if possible
- Delay slow DOM node removal to not block the UI
- Fix global time range syncing when adding timelines to the state
- Use a Proxy to cache CSS colors instead of querying CSS properties
  on every access
- Set className on newly create DOM nodes instead of adding to the
  classList
- Use bound functions for event handlers that are added multiple times
- Speed up Chunk.getBreackdown
- Use CSS gradient for timeline-track chunk backgrounds, which is an
  order of magnitude faster than the serialised canvas approach

Bug: v8:10644
Change-Id: Ie2d6d5b404f18e920c10c0a6460669fd4d0b20e8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2539947
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71207}