Auto Mute Tabs When Multiple Tabs Audible

This extension lets you control mute status of multiple tabs.  Often while you're listening to something from one tab, another tab starts to make sound. This can be annoying. So this extension will automatically mute the previous tab that was making sound.

It works like a stack - think a stack of cards, only the one on top is visible - similarly, only the last tab that's making sound will be allowed to stay unmuted. Once the current audible tab stops making any sounds, the previous tab will be unmuted again.

There are a few keyboard shortcuts you can use:

Cmd+Shift+0 -> Mute all tabs.
Cmd+Shift+8 -> Mute or unmute the current tab.
Cmd+Shift+9 -> Unmute all tabs  (although, if you have multiple audible tabs, only one will remain unmuted, rest will be muted by extension.)

Any tabs you mute with these shortcuts will not be unmuted by the extension. You have to unmute that tab with one of the shortcuts.

Added an Easter Egg feature - press Cmd+Shift+O to try it. It's not very relevant to this extension, but I don't want to create a new extension just for this functionality which I need.