Bluetooth: Don't attempt a pairing for devices not supporting it.

device/bluetooth/bluetooth_device.h

Index: device/bluetooth/bluetooth_device.h
diff --git a/device/bluetooth/bluetooth_device.h b/device/bluetooth/bluetooth_device.h
index bb363f9083e1880234207a74c1ea0d4616c2c24e..26321bcdb538ad1ac693ad010a9041d47994bee0 100644
--- a/device/bluetooth/bluetooth_device.h
+++ b/device/bluetooth/bluetooth_device.h
@@ -165,6 +165,10 @@ class BluetoothDevice {
   // DEVICE_PERIPHERAL.
   DeviceType GetDeviceType() const;
 
+  // Indicates whether the device is known to support pairing based on its
+  // device class and address.
+  bool IsPairable() const;
+
   // Indicates whether the device is paired with the adapter.
   virtual bool IsPaired() const = 0;