Use WASD to control slider zoom and position.

W -> zoom in
S -> zoom out
A -> move slider left
D -> move slider right

Also made zoom in/out steps less sensitive for scrolling.

Changed timeline arrow key press tests to test via dom interaction via than calling handleKeyboardEvent, handleFocusOutEvent, handleFocusInEvent.
(Still need to figure out how to do this for the scroll wheel events).

Screencast: https://screencast.googleplex.com/cast/NTg2NTUxNDk1MjgxODY4OHxhZDE5YWY0My01Yw

Bug: b/339860582
Test: npm run test:unit:ci
Change-Id: I450a2e5c7f1455fd04dc0c06773c8e3a20c14a1e
3 files changed