Auto Mute Tabs When Multiple Tabs Audible

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "short_name": "Mute Control",
  "name": "Auto Mute Tabs When Multiple Tabs Audible",
  "description": "This extension mutes previous audible tabs when a new tab starts making sound. Toggle mute current tab: Cmd+Shift+8",
  "version": "0.1.0",
  "commands": {
    "mute_toggle": {
      "suggested_key": {
        "default": "Ctrl+Shift+8"
      },
      "description": "Toggle current tab mute"
    },
    "mute_all": {
      "suggested_key": {
        "default": "Ctrl+Shift+0"
      },
      "description": "Mute all audible tabs"
    },
    "unmute_all": {
      "suggested_key": {
        "default": "Ctrl+Shift+9"
      },
      "description": "Un-mute all audible tabs"
    }
  },
  "browser_action": {
    "default_icon": "images/play-circle-o_444444_128.png"
  },
  "icons": {
    "16": "images/play-circle-o_444444_16.png",
    "48": "images/play-circle-o_444444_48.png",
    "128": "images/play-circle-o_444444_128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  }
}