Added gcdPrivate.getDeviceInfo function

chrome/test/data/extensions/api_test/gcd_private/api/device_info.js

+// Copyright 2015 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.
+
+onload = function() {
+  chrome.test.runTests([
+    function deviceInfo() {
+      function onDeviceInfo(status, info) {
+        chrome.test.assertEq("success", status);
+        chrome.test.assertEq(info["version"], "3.0");
+        window.setTimeout(chrome.test.notifyPass,3000);
+      }
+
+      chrome.gcdPrivate.getDeviceInfo("myService._privet._tcp.local",
+                                      onDeviceInfo);
+    }
+  ]);
+};