Clarifying behavior of multiple simultaneous shares

[marcoscaceres]

We probably want to clarify what happens when multiple concurrent shares are triggered by user activation. Consider:

var b = document.createElement("button");
document.body.appendChild(b);
b.innerHTML = "hello!";
b.onclick = () => {
    var  p1 =  navigator.share({text: "i am 1", title: "i am 1"});
    var  p2 =  navigator.share({text: "i am 2", title: "i am 2"});
    p1.then(()=>console.log("1 resolved")).catch(err =>  console.error(1, err));
    p2.then(()=>console.log("2 resolved")).catch(err =>  console.error(2, err));
}

Should p1 win and p2 automatically gets rejected with an AbortError? or should p1 get rejected, and p2 wins?

Safari currently shares p1, but rejects both with AbortErrors (even though the share is successful). That seems like a bug.

In any case, seems like if p1 should win and trying to make subsequent calls to share() should reject with an InvalidStateError (i.e., only allow one share at a time per document).