Use USB mojom interfaces in UsbChooserController.

This CL converted USB requests in UsbChooserController to mojom
interfaces through UsbChooserContext.

Bug: 699790
Change-Id: Ib55b8ab0d9a2e891227886eb68cdc29992779f45
Reviewed-on: https://chromium-review.googlesource.com/1235613
Commit-Queue: Donna Wu <donna.wu@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594326}
4 files changed