Add bluetooth device type icons on MD system tray.

device/bluetooth/bluetooth_common.h

Index: device/bluetooth/bluetooth_common.h
diff --git a/device/bluetooth/bluetooth_common.h b/device/bluetooth/bluetooth_common.h
index ae4e13bf06ee54e8160ee2ae4b361404d8f63180..6045980f9b4349f38942fb37021a163bfd6fd5a6 100644
--- a/device/bluetooth/bluetooth_common.h
+++ b/device/bluetooth/bluetooth_common.h
@@ -24,6 +24,26 @@ enum BluetoothTransport : uint8_t {
       (BLUETOOTH_TRANSPORT_CLASSIC | BLUETOOTH_TRANSPORT_LE)
 };
 
+// Possible values that may be returned by BluetoothDevice::GetDeviceType(),
+// representing different types of bluetooth device that we support or are aware
+// of decoded from the bluetooth class information.
+enum class BluetoothDeviceType {
+  UNKNOWN,

[fukino, 2016/10/05 06:34:45]

BLUETOOTH_DEVICE_TYPE_UNKNOWN is more consistent with values of
BluetoothTransport in this file.

However, it doesn't look common in chromium to add prefixes for enum class
members, so I simply used "UNKNOWN", "COMPUTER", etc...

[ortuno, 2016/10/05 06:59:11]

Makes sense. I think we added the prefix to BluetoothTransport because it's only
an enum rather than an enum class.

+  COMPUTER,
+  PHONE,
+  MODEM,
+  AUDIO,
+  CAR_AUDIO,
+  VIDEO,
+  PERIPHERAL,
+  JOYSTICK,
+  GAMEPAD,
+  KEYBOARD,
+  MOUSE,
+  TABLET,
+  KEYBOARD_MOUSE_COMBO
+};
+
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_TYPES_H_