[CrOS MultiDevice] Adjust BLE failure types.

This CL:
(1) Changes the potential failure reasons in the top-level Mojo API. The
    LOCAL_DEVICE_INVALID_BEACON_SEEDS and
    REMOTE_DEVICE_INVALID_BEACON_SEEDS enum values are removed and
    replaced with a COULD_NOT_GENERATE_ADVERTISEMENT value instead.
(2) Updates the BleInitiatorFailureType and BleListenerFailureType enums
    accordingly.
(3) Updates PendingBleInitiatorConnectionRequest and
    PendingBleListenerConnectionRequest to handle the changed failure
    types.
(4) Adds operator<<() functions for both changed failure types.

Bug: 824568, 752273
Change-Id: I29ebf6ad7f232ef51dc462df968287d2124d86e3
Reviewed-on: https://chromium-review.googlesource.com/1093437
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565800}
10 files changed