Random color for YouTube's progress bar

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Random color for YouTube's progress bar",
  "description": "Change red color for a random of the YouTube's progress bar",
  "version": "1.1",
  "content_scripts": [
    {
      "js": [
        "script.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "img/icon.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "128": "img/icon_128.png"
  },
  "background": {
    "scripts": [
      "script.js"
    ]
  }
}