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

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

Index: chrome/test/data/extensions/api_test/identity/test.js
===================================================================
--- chrome/test/data/extensions/api_test/identity/test.js	(revision 137883)
+++ chrome/test/data/extensions/api_test/identity/test.js	(working copy)
@@ -10,5 +10,13 @@
     chrome.experimental.identity.getAuthToken(pass(function(token) {
       assertEq("auth_token", token);
     }));
+  },
+
+  function launchAuthFlow() {
+    chrome.experimental.identity.launchWebAuthFlow(
+        {url: "https://some/url"},
+        pass(function(url) {
+      assertEq("https://abcd.chromiumapp.org/cb#access_token=tok", url);
+    }));
   }
 ]);