Clean up: delete unused methods

Test: rebuild
Change-Id: I144ebbdaf137ee091af949a9e38f68d02941f705

src/com/android/settings/connecteddevice/usb/UsbDetailsFragment.java

@@ -17,7 +17,6 @@
 package com.android.settings.connecteddevice.usb;
 
 import android.content.Context;
-import android.os.Bundle;
 import android.provider.SearchIndexableResource;
 
 import androidx.annotation.VisibleForTesting;
@@ -68,15 +67,6 @@ public class UsbDetailsFragment extends DashboardFragment {
         return R.xml.usb_details_fragment;
     }
 
-    @Override
-    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
-        super.onCreatePreferences(savedInstanceState, rootKey);
-    }
-
-    public boolean isConnected() {
-        return mUsbReceiver.isConnected();
-    }
-
     @Override
     protected List<AbstractPreferenceController> createPreferenceControllers(Context context) {
         mUsbBackend = new UsbBackend(context);