android: Show Policy Chosen Objects in Settings

This change updates the Site Settings UI to differentiate policy and
user granted chosen objects. This change also enables the
WebUsbAllowDevicesForUrls policy for Android, since it is the first use
case of policy managed chosen objects.

Design doc:

Bug: 931459
Change-Id: I2e12f0812f45f31ab5bbecf69a5d7ca5a8c1fbb3
https: //docs.google.com/document/d/1MPvsrWiVD_jAC8ELyk8njFpy6j1thfVU5aWT3TCWE8w/preview#heading=h.z7uyjhrr3ac2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504236
Reviewed-by: Theresa <[email protected]>
Reviewed-by: Becky Zhou <[email protected]>
Reviewed-by: Pavol Marko <[email protected]>
Reviewed-by: Finnur Thorarinsson <[email protected]>
Commit-Queue: Ovidio de Jesús Ruiz-Henríquez <[email protected]>
Cr-Commit-Position: refs/heads/master@{#645886}
17 files changed