Sound sometimes gone or delayed in full-screen on Safari

[rea-laura]

Test Device

Dirac

Operating System

MacOS 10.12.6

Browser

Safari 12.0.2

Problem Description

For phetsims/qa#259
Sound sometimes disappears in full-screen mode. May be related to phetsims/resistance-in-a-wire#190, but happens much more frequently than I observed in resistance in a wire, and is seen in the original sim, iFrame, and XHTML. Only happens in Safari - not yet observed in Chrome or Firefox.

Steps to Reproduce

1. open sim in Safari
2. interact in a way that causes a sound. Note that there is sound
3. put sim in full-screen mode. Try to make a sound again. Often, the sound is now inactive.
4. if the sound is now inactive, exit full-screen mode. Note that the sound is still inactive.
5. switch to another tab in the browser, then switch back. Sometimes, switching back to the sim tab will cause the sound that failed to play earlier to suddenly occur.
6. if this doesn't reproduce issue, try again.

[ariel-phet]

We will investigate after 1.0 is published, not a blocking issue

[jbphet]

This is almost certainly due to the same problem seen in phetsims/resistance-in-a-wire#190 where the audio context goes into an "interrupted" state. The Fractions sim uses the older vibe library, this probably should go away when we port it to use tambo, see phetsims/vibe#33.