How to debug Google Chrome background script?

Question

I have very simple extension:

manifest.json

{
  "name": "historyCleaner",
  "version": "0.1.1",
  "manifest_version": 1,
  "description": "This is my first Chrome extension",
  "background": {
    "scripts": ["cleaner.js"]
  }, 
  "permissions": [
    "history"
  ]
}

cleaner.js

chrome.history.onVisited.addListener(function(HistoryItem result) {

  console.log("it works!");
  alert("it works!");

});

I've loaded it in Google Chrome, it is turned on and... it doesn't work. It doesn't log anything in console, it doesn't alert anything and what is worse, I can't find it in developers tools "Scripts" tab. How can I find why it doesn't work?

//edit

I've changed manifest.json to this one:

{
  "name": "historyCleaner",
  "version": "0.1.5",
  "manifest_version": 1,
  "description": "This is my first Chrome extension",
  "background_page": "background.html",
  "permissions": [
    "history",
    "background"
  ]
}

And embeded JavaScript in background.html

Answer 1

and also if your console.log("it works!"); does not show up, then that's mean chrome.history.onVisited is not fired yet.

ps: For function(HistoryItem result), you may want to change it to function(result).