Filter available notification assts

import android.content.ComponentName;

import android.content.Context;

import android.content.pm.PackageItemInfo;

import android.content.pm.PackageManager;

import android.content.pm.ServiceInfo;

import android.graphics.drawable.Drawable;

import android.os.RemoteException;

import android.provider.SearchIndexableResource;

import android.provider.Settings;

import android.service.notification.NotificationAssistantService;

import android.text.TextUtils;

import android.util.Log;

import com.android.internal.annotations.VisibleForTesting;

import com.android.settings.R;

        List<CandidateInfo> list = new ArrayList<>();

        services.sort(new PackageItemInfo.DisplayNameComparator(mPm));

        for (ServiceInfo service : services) {

            if (mContext.getPackageManager().checkPermission(

                    android.Manifest.permission.REQUEST_NOTIFICATION_ASSISTANT_SERVICE,

                    service.packageName) == PackageManager.PERMISSION_GRANTED) {

                final ComponentName cn = new ComponentName(service.packageName, service.name);

                list.add(new DefaultAppInfo(mContext, mPm, mUserId, cn));

            }

        }

        list.add(new CandidateNone(mContext));

        mCandidateInfos = list;

    }