Simple Ruler

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Simple Ruler",
  "description": "This extension measures segments on the current tab and their slopes",
  "version": "0.1",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "./styles.css"
      ],
      "js": [
        "./script.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "./background.js"
    ]
  },
  "icons": {
    "128": "./icon_128.png"
  },
  "browser_action": {
    "default_icon": "./icon_128.png"
  }
}