Remove test-purpose constructor from AvailableMediaBluetoothDeviceUpdater

- replace mock object with ShadowCachedBluetoothDeviceManager to test CachedBluetoothDevice
- rename cachedDevices to mCachedDevices

Bug: 111848213
Test: make -j50 RunSettingsRoboTests
Change-Id: I3028a6fe06c39c48e7cee33976bdfcab2c8b73c8

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

@@ -23,9 +23,7 @@ import android.util.Log;
 import com.android.settings.connecteddevice.DevicePreferenceCallback;
 import com.android.settings.dashboard.DashboardFragment;
 import com.android.settingslib.bluetooth.CachedBluetoothDevice;
-import com.android.settingslib.bluetooth.LocalBluetoothManager;
 
-import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
 
 /**
@@ -45,15 +43,6 @@ public class AvailableMediaBluetoothDeviceUpdater extends BluetoothDeviceUpdater
         mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
     }
 
-    @VisibleForTesting
-    AvailableMediaBluetoothDeviceUpdater(DashboardFragment fragment,
-            DevicePreferenceCallback devicePreferenceCallback,
-            LocalBluetoothManager localBluetoothManager) {
-        super(fragment, devicePreferenceCallback, localBluetoothManager);
-        mAudioManager = (AudioManager) fragment.getContext().
-                getSystemService(Context.AUDIO_SERVICE);
-    }
-
     @Override
     public void onAudioModeChanged() {
         forceUpdate();