GitLab

This is a reland of 706a5c51

The original CL got reverted because of a bug in the code that is now
used with the CL. Fix landed here: crrev.com/c/2320174. No changes were
required for this CL.

Original change's description:
> [Nearby] Start discovery on discovery page
>
> This calls the DiscoveryManager interface from JS and listens for
> discovered and lost devices to update the device list. The selected
> device is then passed through to the confirmation-page.
>
> Bug: 1103190
> Change-Id: I9296e5449533eb869fd9f20fe442d4ac1bc05a42
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2315862
> Commit-Queue: Richard Knoll <knollr@chromium.org>
> Reviewed-by: Michael van Ouwerkerk <mvanouwerkerk@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#791591}

TBR=mvanouwerkerk@chromium.org

Bug: 1103190
Change-Id: I2abe1135599fa190d29a42f64ef0a7ed206f4281
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2320871
Commit-Queue: Richard Knoll <knollr@chromium.org>
Reviewed-by: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792061}