title: Cookies permission in Chrome extension doesn't work
body: <p>I'm having problem with my Chrome extension when I try adding cookies permission.
  First, the manifest file is like this</p>
  
  <pre><code>"permissions": [
      "cookies",
      "https://api.box.com/*", 
      "https://www.box.com/api/*",
      "https://dl.boxcloud.com/*",
      "tabs",
      "identity",
    ],
  </code></pre>
  
  <p>But when I click to the permission properties of my extension in chrome://extensions/, there is no <code>cookies</code> permission showing up. I'm not sure whether it is problematic or not, please help me clarify.</p>
  
  <p>The main problem is, when I run the code:</p>
  
  <pre><code>getCookies("https://www.box.com", "tokens", function(tokens){
          console.log("Token returned");     
  });
  
  function getCookies(domain, name, callback) {
      console.log("Getting cookies...");
      chrome.cookies.get({"url": domain, "name": name}, function(cookie) {
          if(callback){
              console.log("Done getting cookies, calling back...");                    
              callback(cookie.value);
          }
      });
  }
  </code></pre>
  
  <p>The <code>callback</code> function is never called, thus the <code>Token returned</code> message is never printed. I could see the <code>"Done getting cookies, calling back..</code> message in the console. So why is this happening? Please help me resolve it...</p>