MD Settings: Add remaining buttons to keyboard subpage

chrome/test/data/webui/settings/device_page_tests.js

 // Copyright 2016 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.
 
 cr.define('settings_device_page', function() {
   /**
    * @constructor
    * @implements {settings.DevicePageBrowserProxy}
    */
-  function TestDevicePageBrowserProxy() {}
+  function TestDevicePageBrowserProxy() {
+    this.keyboardShortcutsOverlayShown_ = 0;
+  }
 
   TestDevicePageBrowserProxy.prototype = {
     /** @override */
     handleLinkEvent: function(e) {
       settings.DevicePageBrowserProxyImpl.prototype.handleLinkEvent.call(
           this, e);
       // Prevent opening the link, which can block the test.
       e.preventDefault();
     },
+
+    /** override */
+    initializeKeyboard: function() {},
+
+    /** override */
+    showKeyboardShortcutsOverlay: function() {
+      this.keyboardShortcutsOverlayShown_++;
+    },
   };
 
   suite('SettingsDevicePage', function() {
     var fakePrefs = {
       settings: {
         touchpad: {
           enable_tap_to_click: {
             key: 'settings.touchpad.enable_tap_to_click',
             type: chrome.settingsPrivate.PrefType.BOOLEAN,
             value: true,
@@ skipping 203 matching lines @@
       devicePage.set(
           'prefs.settings.language.xkb_auto_repeat_delay_r2.value', 600);
       expectEquals(keyboardPage.$.delaySlider.immediateValue, 3 /* 500 */);
       devicePage.set(
           'prefs.settings.language.xkb_auto_repeat_interval_r2.value', 45);
       expectEquals(keyboardPage.$.repeatRateSlider.immediateValue, 6 /* 50 */);
 
       devicePage.set(
           'prefs.settings.language.xkb_auto_repeat_enabled_r2.value', false);
       expectFalse(collapse.opened);
+
+      // Test keyboard shortcut overlay button.
+      MockInteractions.tap(keyboardPage.$$('#keyboardOverlay'));
+      expectEquals(
+          1,
+          settings.DevicePageBrowserProxyImpl.getInstance()
+              .keyboardShortcutsOverlayShown_);
     });
 
     // Test more edge cases for slider rounding logic.
     // TODO(michaelpg): Move this test to settings-slider tests once that
     // element is created.
     test('keyboard sliders', function() {
       var keyboardPage = showAndGetDeviceSubpage('keyboard');
       assertTrue(!!keyboardPage);
 
       var testArray = [80, 20, 350, 1000, 200, 100];
@@ skipping 107 matching lines @@
                 expectTrue(displayPage.showMirror_(displayPage.displays));
                 expectTrue(displayPage.isMirrored_(displayPage.displays));
               });
             });
           });
         });
       });
     });
   });
 });