Add userVisibleOnly to web_sys::PushSubscriptionOptionsInit

[johnsonw]

Motivation

I would like to subscribe to push notifications using a service worker. This can easily be achieved by calling the subscribe function on the PushManager. The subscribe function takes an object with the following properties:

1. userVisibleOnly
2. applicationServerKey

• See mdn docs: https://developer.mozilla.org/en-US/docs/Web/API/PushManager/subscribe

web-sys currently supports the applicationServerKey but does not include support for the userVisibleOnly property:
https://docs.rs/web-sys/0.3.44/web_sys/struct.PushSubscriptionOptionsInit.html

If this property is not set to true, subscribing with an application server key will fail.

Proposed Solution

I would like to add the userVisibleOnly property to web-sys::PushSubscriptionOptionsInit.

Alternatives

I do not have any alternatives at this time.

Additional Context

Without setting this property to true, the subscription will fail. Here is the error message I receive:

Chrome currently only supports the Push API for subscriptions that will result in user-visible messages. You can indicate
this by calling pushManager.subscribe({userVisibleOnly: true}) instead. See https://goo.gl/yqv4Q4 for more details.
index_bg.js?6119:336 panicked at 'Couldn't subscribe to push manager.: JsValue(NotAllowedError: Registration failed -
permission denied

Here is an example of how I am subscribing to push notifications with service worker:

fn url_b64_to_uint_8_array(base_64_string: &str) -> js_sys::Uint8Array {
    let padding = std::iter::repeat('=').take((4 - (base_64_string.len() % 4)) % 4).collect::<String>();
    let base64 = format!("{}{}", base_64_string, &padding).replace('-', "+").replace('_', "/");
    let window = web_sys::window().expect("Couldn't get window.");
    
    let raw_data: String = window.atob(&base64).expect("couldn't call atob.");
    let output_array: js_sys::Uint8Array = js_sys::Uint8Array::new_with_length(raw_data.chars().count() as u32);
    

    let mut pos = 0;
    for c in raw_data.chars() {
        log!("Setting value", c, "in position", pos);
        output_array.set_index(pos, c as u8);
        pos = pos + 1;
    }

    output_array
}

        let window = web_sys::window().expect("Couldn't get window.");
        let sw_container = window.navigator().service_worker();

        let p = sw_container.register("/service-worker.js");
        let reg = wasm_bindgen_futures::JsFuture::from(p).await;

        if let Ok(reg) = reg {
            let sw_reg: web_sys::ServiceWorkerRegistration = reg.into();
            let manager: web_sys::PushManager = sw_reg.push_manager().unwrap();

            let mut subscription_options = web_sys::PushSubscriptionOptionsInit::new();
            let key = "<key>";
            let encoded_key = url_b64_to_uint_8_array(key);

            subscription_options.application_server_key(
                Some(&encoded_key)
            );
            //subscription_options.user_visible_only(Some(true));   <-- This is where I would like to set the userVisibleOnly property


            let subscribe = manager.subscribe_with_options(&subscription_options).unwrap();
            wasm_bindgen_futures::JsFuture::from(subscribe).await.expect("Couldn't subscribe to push manager.");

            if let Some(x) = sw_reg.installing() {
                log!("Service worker installing.");
            } else if let Some(x) = sw_reg.waiting() {
                log!("Service worker waiting.");
            } else if let Some(x) = sw_reg.active() {
                log!("Service worker active.");
            }
        } else {
            log!("Error registering service worker.");
        }