Add preference click metric logs for some special cases

Bug: 137559984
Test: visual, robotest
Change-Id: If8624b49abcd0000487065160ce4a7ba861f234c

src/com/android/settings/bluetooth/ConnectedBluetoothDeviceUpdater.java

@@ -35,6 +35,8 @@ public class ConnectedBluetoothDeviceUpdater extends BluetoothDeviceUpdater {
     private static final String TAG = "ConnBluetoothDeviceUpdater";
     private static final boolean DBG = false;
 
+    private static final String PREF_KEY = "connected_bt";
+
     private final AudioManager mAudioManager;
 
     public ConnectedBluetoothDeviceUpdater(Context context, DashboardFragment fragment,
@@ -111,4 +113,9 @@ public class ConnectedBluetoothDeviceUpdater extends BluetoothDeviceUpdater {
             });
         }
     }
+
+    @Override
+    protected String getPreferenceKey() {
+        return PREF_KEY;
+    }
 }