- Add ToolTip helper that tracks scrolling target elements
- Auto hide if the target scrolls out of view
- ToolTip position depends on target position
- Add basic tooltips for maps in the transition view, entries in
  timeline tracks and the source panel

Drive-by-fix:
- Move events.mjs to view/ folder
- Add basic toString methods on various log entries
- Add requestAnimationFrame update support for V8CustomElement

Bug: v8:10644
Change-Id: I1059733cd094a986b715547b3d5747eefbc54bc5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2551103
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71434}