private void createAndShowNotification() {
        NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(this)
                        .setSmallIcon(R.drawable.abc_popup_background_mtrl_mult)
                        .setContentTitle(getString(R.string.notification_title))
                        .setContentText(getString(R.string.notification_text));

        Intent resultIntent = new Intent(
                this.getApplicationContext(), NotificationParentActivity.class);

        resultIntent.putExtra(
                NotificationParentActivity.EXTRA_URL, getString(R.string.notification_sample_url));

        resultIntent.setAction(Intent.ACTION_VIEW);

        PendingIntent pendingIntent = PendingIntent.getActivity(
                this.getApplicationContext(), 0, resultIntent, 0);

        mBuilder.setContentIntent(pendingIntent);
        mBuilder.setAutoCancel(true);
        NotificationManager mNotificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        // mId allows you to update the notification later on.
        mNotificationManager.notify(NOTIFICATION_ID, mBuilder.build());
    }
This is the Activity that the Notification takes the user to.

The Notification sends the user to this activity with an EXTRA_URL. Use it to call Chrome Custom
Tabs. The user will return to it when coming back from the web content.
demos/src/main/java/org/chromium/customtabsdemos/NotificationParentActivity.java