Pixel perfect tools

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Pixel perfect tools",
  "description": "This extension will allow you to work pixel perfect",
  "version": "1.0",
  "browser_action": {
    "default_icon": "Pencil-icon-small.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*"
      ],
      "css": [
        "mystyles.css"
      ],
      "js": [
        "popup.js"
      ]
    }
  ]
}