[Bluetooth] Standardize Bluetooth device address format to XX:XX:XX:XX:XX:XX.

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 a1825948b3c8b2354b23b9a2d2f4124987cbb355..14365baa24cda61628cd98267c2fc1ea8d433624 100644
--- a/device/bluetooth/bluetooth_device.h
+++ b/device/bluetooth/bluetooth_device.h
@@ -418,6 +418,11 @@ class BluetoothDevice {
   virtual BluetoothGattService* GetGattService(
       const std::string& identifier) const;
 
+  // Returns the |address| in the canoncial format: XX:XX:XX:XX:XX:XX, where
+  // each 'X' is a hex digit.  If the input |address| is invalid, returns an
+  // empty string.
+  static std::string CanonicalizeAddress(const std::string& address);
+
  protected:
   BluetoothDevice();