Add the browser test for the new gallery.

chrome/test/data/extensions/api_test/file_manager_browsertest/tab_index.js

-// Copyright (c) 2014 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.
-
-'use strict';
-
-/**
- * Tests the focus behavior of the search box.
- */
-testcase.searchBoxFocus = function() {
-  var appId;
-  StepsRunner.run([
-    // Set up File Manager.
-    function() {
-      setupAndWaitUntilReady(null, RootPath.DRIVE, this.next);
-    },
-    // Check that the file list has the focus on launch.
-    function(inAppId) {
-      appId = inAppId;
-      waitForElement(appId, ['#file-list:focus']).then(this.next);
-    },
-    // Press the Ctrl-F key.
-    function(element) {
-      callRemoteTestUtil('fakeKeyDown',
-                         appId,
-                         ['body', 'U+0046', true],
-                         this.next);
-    },
-    // Check that the search box has the focus.
-    function(result) {
-      chrome.test.assertTrue(result);
-      waitForElement(appId, ['#search-box input:focus']).then(this.next);
-    },
-    // Press the Tab key.
-    function(element) {
-      callRemoteTestUtil('fakeKeyDown',
-                         appId,
-                         ['body', 'U+0009', false],
-                         this.next);
-    },
-    // Check that the file list has the focus.
-    function(result) {
-      chrome.test.assertTrue(result);
-      waitForElement(appId, ['#file-list:focus']).then(this.next);
-    },
-    // Check for errors.
-    function(element) {
-      checkIfNoErrorsOccured(this.next);
-    }
-  ]);
-};