Chrome扩展程序onMessage侦听器无法正常工作

Question

我有一个这样的清单文件：

{
  "name": "Thing",
  "description": "blah blah.",
  "version": "1.0",
  "manifest_version": 2,
  "icons": { 
    "16": "icon-16.png",
    "32": "icon-32.png",
    "180": "icon-180.png" 
  },
  "browser_action": {
    "default_icon": "icon-32.png",
    "default_title": "Fundstack",
    "default_popup": "browser_action/browser_action.html"
  },
  "background": {
    "scripts": [
      "env.js", 
      "node_modules/auth0-chrome/dist/auth0chrome.min.js", 
      "auth.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*",
        "https://inbox.google.com/*"
      ],
      "js": ["vendor/jquery.min.js", "vendor/underscore-min.js", "vendor/moment.min.js", "inboxsdk.js", "content.js", "node_modules/auth0-chrome/dist/auth0chrome.min.js"],
      "css": ["styles.css"],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "https://mail.google.com/",
    "https://inbox.google.com/",
    "https://logo.clearbit.com/",
    "identity",
    "notifications",
    "activeTab"
  ],
  "web_accessible_resources": [
    "sidebarTemplate.html",
    "icon-*.png"
  ]
}

在browser_action.js我有这个：

const loginBtn = $('.login-btn');

loginBtn.click(() => {
    console.log('Click!');
    chrome.runtime.sendMessage({
      type: "authenticate"
    });
});

在auth.js我有这个：

chrome.runtime.onMessage.addListener(function(event) {

  console.log('event!!!!');

  return true;

});

当我点击时，我在控制台中获得Click!，但不是event!!!!。我错过了什么明显的东西？