I got this report from a developer via email.

Chrome Version: Unknown
OS: Android (assumed)

What steps will reproduce the problem?

  let url = canvasElement.toDataURL('image/png');

  navigator.share({
    title: document.title,
    text: 'Sample text',
    url: url
  }).then(() => console.log('Successful share'))
  .catch(error => console.log('Error sharing:', error));

(Note: the developer told me "I was clicking on a button in the same way as with the sharing of a regular URL", so apparently the call to navigator.share is in a click handler.)

What is the expected result?
Not clear (since it's a data URI). Either the URI is delivered to the target application as a URI, or it's converted to a file object, or some other meaningful error.

What happens instead?
"Error sharing: DOMException: Must be handling a user gesture to perform a share request."

If indeed this is on a button click handler, the error message doesn't make sense.