title: Callback not called for chrome.identity.getAuthToken for self hosted chrome extension
body: <p>I am developing a self hosted chrome extension and have generated the key and client_id as described <a href="https://stackoverflow.com/questions/23873623/obtaining-chrome-extension-id-for-development">here</a>. My call to getAuthToken is (copied from the answer to <a href="https://stackoverflow.com/questions/25044936/chrome-identity-user-authentication-in-a-chrome-extension">this question</a>)</p>
  
  <pre><code>chrome.identity.getAuthToken({
      interactive: true
  }, function(token) {
      if (chrome.runtime.lastError) {
          alert(chrome.runtime.lastError.message);
          return;
      }
      var x = new XMLHttpRequest();
      x.open('GET', 'https://www.googleapis.com/oauth2/v1/userinfo?alt=json&amp;access_token=' + token);
      x.onload = function() {
          alert(x.response);
      };
      x.send();
  });
  </code></pre>
  
  <p>However I find that while the user is correctly directed to the google login page, <strong>my call back is never called</strong> after the user is correctly authenticated. My question: Is it the case that I have to register my application with Google (rather than use a self-generated key pair, key and client_id) for my callback to be called? For a test application registered with google, the same callback is correctly called. </p>
  
  <p>My manifest file has</p>
  
  <pre><code>    "permissions": [
          "background",
          ...
          "identity",
          "*://*/*"
      ],
      "key" : "Long key here",
      "oauth2" : {
              "client_id" : "Id of length 32",
              "scopes" : [
                  "https://www.googleapis.com/auth/plus.login"
              ]
      }
  </code></pre>
  
  <p>Thank you.</p>