This CL deletes the image on the timeline overview which
only reflects the last uploaded timeline-track data
and updates the timelineOverviewIndicator on mousemove and
chunk zoom events.

Bug: v8:10644

Change-Id: Ib0a43083d2461cc343a0c946cfddaf4fdc514687
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2413257Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#69936}