UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.79 Safari/537.36

Steps to reproduce the problem:
1. Open a page with a web share button, such as https://santatracker.google.com/village.html
2. Click the share button

What is the expected behavior?
If the browser/platform has share targets, it should show a UI for choosing a target (or cancel) and allow sharing. If the platform does not have at least 1 share target, the UI should not display.

What went wrong?
An empty web share UI opened with no available web share targets.

Did this work before? No 

Chrome version: 61.0.3163.79  Channel: stable
OS Version: Fedora 26
Flash Version: 

Per the spec for web share, if there are no share targets, a promise should return with AbortError rather than displaying the UI. See section 2.1.1 here: https://wicg.github.io/web-share/

It also seems like section 2.1 insinuates that navigator.share should not even exist for the purpose of feature detection in this case:

"If share is present, there is a reasonable expectation that it will work and present the user with at least one share target."

But I can also see the value of displaying the empty share UI with options for adding a new share target, so perhaps that's an opportunity to alter the spec.