title: Swift WKWebView "Error acquiring assertion" after updating to Xcode 11
body: <p>I appreciate help to resolve the following problem.
  This problem appeared after I updated to Xcode 11.</p>
  
  <p>A WKWebView opens a web page that contains an embedded Vimeo video.
  The page loads and displays the embedded player.
  When I tap on the video to play it, I received the following errors in the console:</p>
  
  <blockquote>
    <p>[assertion] Error acquiring assertion:  {
        userInfo = {
            RBSAssertionAttribute = ;
        } }</p>
    
    <p>[ProcessSuspension]  0x1056fde38 - ProcessAssertion() PID 1887 Unable
    to acquire assertion for process with PID 1887 2019-09-22
    11:15:04.570119-0700 testWeb[1887:362082] [ProcessSuspension]
    0x1056fde38 - ProcessAssertion::processAssertionWasInvalidated()
    2019-09-22 11:15:04.576732-0700 testWeb[1887:362143] [assertion] Error
    acquiring assertion:  {
        userInfo = {
            RBSAssertionAttribute = ;
        } }</p>
    
    <p>[ProcessSuspension]  0x1056fde88 - ProcessAssertion() PID 1887 Unable
    to acquire assertion for process with PID 1890 2019-09-22
    11:15:04.577137-0700 testWeb[1887:362082] [ProcessSuspension]
    0x1056fde88 - ProcessAssertion::processAssertionWasInvalidated()
    2019-09-22 11:15:05.261258-0700 testWeb[1887:362150] [plugin]
    AddInstanceForFactory: No factory registered for id  F8BB1C28-BAE8-11D6-9C31-00039315CD46</p>
  </blockquote>
  
  <p>This is running on Xcode 11 and the problem appears on the simulator and on devices running iOS 13 and iOS 12.</p>