Activity detection for Adaptive screen saver

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Activity detection for Adaptive screen saver",
  "description": "Detects playback of HTML5 <video> elements.",
  "version": "0.0.2",
  "icons": {
    "16": "icon/16.png",
    "24": "icon/24.png",
    "48": "icon/48.png",
    "64": "icon/64.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "all_frames": true,
      "js": [
        "script/content.js"
      ]
    }
  ]
}