Extend the enterprise.deviceAttributes API

Extend the enterprise.deviceAttributes API to provide the device
serial number, the administrator-annotated Asset ID and the
administrator-set annotated location.
The new functions are only available to force-installed extensions
running in an affiliated user profile.

API proposal:
https://docs.google.com/a/chromium.org/document/d/1NDt1enxSbKrbwo-BH4qgCbg2M5EWB6igkpe1le0Egk0

Bug: 803974
Test: browser_tests --gtest_filter=*EnterpriseDeviceAttributes*

Change-Id: I48b3e070a953efe01491e8b9de2700758e158d26
Reviewed-on: https://chromium-review.googlesource.com/876365
Commit-Queue: Pavol Marko <[email protected]>
Reviewed-by: Istiaque Ahmed <[email protected]>
Reviewed-by: Devlin <[email protected]>
Reviewed-by: Maksim Ivanov <[email protected]>
Reviewed-by: Ilya Sherman <[email protected]>
Cr-Commit-Position: refs/heads/master@{#536985}
12 files changed