bluetooth: add DisplayPinCode method

Our bluetoothd is patched to call DisplayPinCode on the agent when
pairing with Bluetooth 2.0 and older keyboards. Add this method to
the bluetooth_agent interface.

BUG=chromium-os:27101
TEST=none

Change-Id: I749a449b06a8673be93145dc292a18bb4424edbe
1 file changed
tree: 33b904549d2b96a20524fe94201b726c11301e6a
  1. README
  2. dbus/
  3. window_manager/