Merge "adb: use a custom thread to poll for usb devices on mac." am: 28d7c54
am: 507f38f

* commit '507f38f6d7e8dcae4b513ea6c5f638ae43204245':
  adb: use a custom thread to poll for usb devices on mac.

Change-Id: Idc21e33a8b0942afe0f6fa18076718d71d9d34f6