GitLab

Demo: https://screenshot.googleplex.com/47REAoUwTx7sigJ.png

This CL:
1. Introduces |PhoneHubInterstitialView| with a customized layout that
   can be reused by onboarding, disconnecting/connecting and error
   state UI.
2. Introduces |OnboardingView| which serves as an entry point for
   eligible users to set up the Phone Hub feature.

Remaining work includes implementing the button click handlers.

BUG=1106937,1126208

Change-Id: Ib1b93b47ee1b715c991811b35afdfdc57b2f5c7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406662
Commit-Queue: Meilin Wang <meilinw@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807766}