@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_notification_parent);
        mMessageTextView = findViewById(R.id.back_to_app_message);
        mCreateNotificationButton = findViewById(R.id.create_notification);
        mCreateNotificationButton.setOnClickListener(this);
        startChromeCustomTab(getIntent());
    }
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