Files: Add a shortcut Alt-E to open gear menu.

ui/file_manager/integration_tests/file_manager/gear_menu.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.
 
 'use strict';
 
 /**
  * Expected files shown in Downloads with hidden enabled
  *
  * @type {!Array<!TestEntryInfo>}
@@ skipping 48 matching lines @@
  * hidden
  * @return {!Array} The test steps to toggle hidden files
  */
 function getTestCaseStepsForHiddenFiles(basicSet, hiddenEntrySet) {
   var appId;
   return [
     function(id) {
       appId = id;
       remoteCall.waitForElement(appId, '#gear-button').then(this.next);
     },
-    // Click the gear menu.
+    // Open the gear menu by clicking the gear button.
     function() {
       remoteCall.callRemoteTestUtil(
           'fakeMouseClick', appId, ['#gear-button'], this.next);
     },
     // Wait for menu to not be hidden.
     function(result) {
       chrome.test.assertTrue(result);
       remoteCall.waitForElement(appId, '#gear-menu:not([hidden])')
       .then(this.next);
     },
@@ skipping 135 matching lines @@
 testcase.hideGoogleDocs = function() {
   var appId;
   StepsRunner.run([
     function() {
       setupAndWaitUntilReady(null, RootPath.DRIVE).then(this.next);
     },
     function(results) {
       appId = results.windowId;
       remoteCall.waitForElement(appId, '#gear-button').then(this.next);
     },
-    // Click the gear menu.
+    // Open the gear meny by a shortcut (Alt-E).
     function() {
-      remoteCall.callRemoteTestUtil(
-          'fakeMouseDown', appId, ['#gear-button'], this.next);
+      remoteCall.fakeKeyDown(appId, 'body', 'U+0045', false, false, true)
+          .then(this.next);
     },
     // Wait for menu to appear.
     function(result) {
       chrome.test.assertTrue(result);
       remoteCall.waitForElement(appId, '#gear-menu').then(this.next);
     },
     // Wait for menu to appear.
     function(result) {
       remoteCall.waitForElement(appId,
           '#gear-menu-drive-hosted-settings:not([disabled])').then(this.next);
@@ skipping 32 matching lines @@
     function(result) {
       remoteCall.waitForFiles(appId, TestEntryInfo.getExpectedRows(
           BASIC_DRIVE_ENTRY_SET), {ignoreFileSize: true,
           ignoreLastModifiedTime: true}).then(this.next);
     },
     function() {
       checkIfNoErrorsOccured(this.next);
     },
   ]);
 };