Start implementing an auth flow for platform apps to be able to do auth

chrome/test/data/extensions/api_test/identity/test.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var assertEq = chrome.test.assertEq;
 var pass = chrome.test.callbackPass;
 
 chrome.test.runTests([
   function getAuthToken() {
     chrome.experimental.identity.getAuthToken(pass(function(token) {
       assertEq("auth_token", token);
     }));
+  },
+
+  function launchAuthFlow() {
+    chrome.experimental.identity.launchAuthFlow(
+        {url: "https://some/url"},
+        pass(function(responseUrl) {
+      assertEq("https://test/url", responseUrl);
+    }));
   }
 ]);