Button to toggle cross tool sync.

Screencast: https://screencast.googleplex.com/cast/NTg3ODAxMjMwMTAxNzA4OHxjNzhkNmVkMi1mMQ

Fixes: 314118256
Test: npm run test:e2e
Change-Id: I2607fd9f8fdbb75bb7154a919abf3b745707713f
4 files changed