private void startChromeCustomTab(Intent intent) {
        String url = intent.getStringExtra(EXTRA_URL);
        if (url != null) {
            Uri uri = Uri.parse(url);

            int tabcolor = getResources().getColor(R.color.primaryColor);
            CustomTabsIntent customTabsIntent = new CustomTabsIntent.Builder()
                    .setToolbarColor(tabcolor)
                    .build();
            CustomTabActivityHelper.openCustomTab(
                    this, customTabsIntent, uri, new WebviewFallback());

            mMessageTextView.setVisibility(View.VISIBLE);
            mCreateNotificationButton.setVisibility(View.GONE);
        } else {
            mMessageTextView.setVisibility(View.GONE);
            mCreateNotificationButton.setVisibility(View.VISIBLE);
        }
    }
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