Allow right click - simple copy

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "background": {
    "page": "background.html"
  },
  "browser_action": {
    "default_title": "Unblock right click - allow copy",
    "default_icon": "images/128px.png",
    "default_popup": "main.html"
  },
  "options_page": "pages/options.html",
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "all_frames": true,
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "icons": {
    "16": "images/16px.png",
    "32": "images/32px.png",
    "48": "images/48px.png",
    "128": "images/128px.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "short_name": "Allow copy",
  "manifest_version": 2,
  "name": "__MSG_name__",
  "description": "__MSG_desc__",
  "default_locale": "en",
  "version": "1.2.9"
}