Fix ownership of BluetoothAdapter in BluetoothDeviceChooserController

BluetoothAdapter is a reference counted object and so
BluetoothDeviceChooserController should own it using a scoped_refptr.
Fixing this requires also fixing BluetoothAdapterFactoryWrapper's
AcquireAdapterCallback to take a scoped_refptr rather than a raw
pointer. A test for proper ownership has been added.

Bug: 1024121
Change-Id: I6342322e059f9cbff2a0d5f073f6bccfb0ca7c36
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1914536
Reviewed-by: Matt Reynolds <mattreynolds@chromium.org>
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715206}
7 files changed