- Show spinner while parsing input
- Show color boxes next transition types
- Support drag-n-drop of v8.log files

No-Try: true
Change-Id: I360d62960e9ec05fbab388ee2ca55baf4e2c6b78
Reviewed-on: https://chromium-review.googlesource.com/c/1345151Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57675}