Changes:

* Transition edges on timeline-track with the same color of the map type.
* Log file reader loading background adapted to light theme.
* Support additional IC log event colors.
* Move theme switch button to top of the app.

Bug: v8:10644, v8:10673

Change-Id: Ib086b6f4a8bc5f86a4925b251112c640e37278ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2379869Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#69600}