Guard against disabled app when launcing emergency dialer

import android.content.Intent;

import android.content.pm.ApplicationInfo;

import android.content.pm.PackageManager;

import android.content.pm.ResolveInfo;

import android.net.Uri;

import android.os.Binder;

import android.os.Build;

                    com.android.internal.R.string.config_emergency_dialer_package);

            Intent intent = new Intent(Intent.ACTION_DIAL_EMERGENCY)

                    .setPackage(packageName);

            ResolveInfo resolveInfo = mPackageManager.resolveActivity(intent, 0 /* flags*/);

            if (resolveInfo == null) {

                // No matching activity from config, fallback to default platform implementation

                intent.setPackage(null);

            }

            if (!TextUtils.isEmpty(number) && TextUtils.isDigitsOnly(number)) {

                intent.setData(Uri.parse("tel:" + number));

            }