Move another set of extension tests to manifest_version 2

chrome/test/data/extensions/api_test/tabs/get_current/a.js

Index: chrome/test/data/extensions/api_test/tabs/get_current/a.js
===================================================================
--- chrome/test/data/extensions/api_test/tabs/get_current/a.js	(revision 0)
+++ chrome/test/data/extensions/api_test/tabs/get_current/a.js	(revision 0)
@@ -0,0 +1,9 @@
+// Copyright (c) 2011 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.
+
+window.onload = function() {
+  chrome.tabs.getCurrent(function(tab) {
+    chrome.extension.getBackgroundPage().onCompleteGetCurrentTab(tab);
+  });
+};