bluetooth: Implement FailingConnectionsAdapter.
Also implement UnconnectableDevice. Used for testing that the platform handles
all connection errors successfully.
Design doc: https://docs.google.com/document/d/1_QsBzcc84SwF7oaBWbO8rBzn39MISQ3w-6QM9hk0L3E/edit?usp=sharing
Three sided patch since we have to remove the old adapter after we modify tests:
[1] This patch.
[2] Add unconnectable device tests and remove old tests. (http://crrev.com/
1244973002)
[3] Remove old UnconnectableDeviceAdapter. (http://crrev.com/
1243803002)
BUG=499552
Review URL: https://codereview.chromium.org/
1247553002
Cr-Commit-Position: refs/heads/master@{#339983}