UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36

Steps to reproduce the problem:
1. Open page http://fiddle.jshell.net/jxcyn0bj/1/show/
2. Open Dev tools, change console to show logs for fiddle.jshell.net
3. Change tab and come back to the page

The relevant code on the demo page is below:

window.addEventListener('visibilitychange', function() {
  console.log('hello');
  debugger;
});

What is the expected behavior?
Console should only print 'hello' once and then stop on debugger

After continuing, hello should have been printed again and debugger hit again.

What went wrong?
'Hello' was printed twice but the breakpoint was hit only once.

Did this work before? N/A 

Chrome version: 51.0.2704.106  Channel: n/a
OS Version: 13.10
Flash Version: Shockwave Flash 22.0 r0