UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36

Steps to reproduce the problem:
    if (navigator.requestMIDIAccess) {
      navigator.requestMIDIAccess().then(onSuccess, onFailure);
    } else {
      console.log("Web MIDI API not supported!");
    }

    function onSuccess(midiAccess) {

      var outputs = [];

      var iter = midiAccess.outputs.values();
      for (var i = iter.next(); i && !i.done; i = iter.next()) {
        outputs.push(i.value);
      }

      outputs[0].send([0xF6]); // tuning request

    }

    function onFailure(error) {
      console.log("Could not connect to the MIDI interface");
    }

What is the expected behavior?
Should work.

What went wrong?
The tune request MIDI message (0xF6) does not need any data bytes. Output.send([0xF6]) should work instead of throwing "Message is incomplete" error.

Did this work before? N/A 

Chrome version: 50.0.2661.94  Channel: stable
OS Version: OS X 10.11.4
Flash Version: Shockwave Flash 21.0 r0