Spotify Web Watcher

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Spotify Web Watcher",
  "version": "1.1.0",
  "description": "Watch over the Spotify Web Player and report the current song, artist and cover",
  "manifest_version": 2,
  "content_security_policy": "script-src 'self' https://www.gstatic.com/ https://*.firebaseio.com https://cdn.firebase.com https://www.googleapis.com; object-src 'self'",
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icons/16x16-green.png",
    "48": "icons/48x48-green.png",
    "128": "icons/128x128-green.png"
  },
  "web_accessible_resources": [
    "icons/*.png"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icons/48x48-white.png",
      "32": "icons/48x48-white.png",
      "48": "icons/48x48-white.png"
    },
    "default_title": "Spotify Web Watcher",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://open.spotify.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}