Use fake Input Device Settings with chrome://device-emulator

chrome/browser/resources/chromeos/emulator/device_emulator_pages.html

 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout-classes.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animated-pages.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/animations/fade-in-animation.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/animations/fade-out-animation.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-drawer-panel/paper-drawer-panel.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-header-panel/paper-header-panel.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-item/paper-icon-item.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-listbox/paper-listbox.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/shadow.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toolbar/paper-toolbar.html">
 <link rel="import" href="audio_settings.html">
 <link rel="import" href="battery_settings.html">
 <link rel="import" href="bluetooth_settings.html">
 <link rel="import" href="icons.html">
+<link rel="import" href="input_device_settings.html">
 <link rel="import" href="shared_styles.html">
 
 <dom-module id="device-emulator-pages">
   <template>
     <!-- TODO(michaelpg): Wrap the line below to fit within the 80-char limit.
          See https://github.com/Polymer/polymer/pull/3668. -->
     <style include="device-emulator-shared-styles iron-flex iron-flex-alignment iron-positioning">
       :host {
         display: flex;
         flex-direction: column;
       }
 
       paper-drawer-panel {
         --paper-drawer-panel-main-container: {
           background-color: #ddd;
         };
       }
 
       paper-drawer-panel header {
         font-weight: bolder;
       }
 
       paper-drawer-panel:not([narrow]) > [main] header {
         display: none;
       }
 
       paper-drawer-panel paper-listbox paper-icon-item {
+        -webkit-margin-start: 20px;
         padding: 10px 5px;
-        -webkit-margin-start: 20px;
       }
 
       neon-animated-pages > * {
         @apply(--shadow-elevation-2dp);
         background-color: white;
         display: block;
         margin: 20px;
+        padding: 0 20px 20px 20px;
         position: relative !important;
-        padding: 0 20px 20px 20px;
       }
     </style>
     <paper-drawer-panel>
       <paper-header-panel drawer>
         <paper-toolbar>
           <header>Chrome OS Device Emulator</header>
         </paper-toolbar>
         <paper-listbox class="layout vertical" selected="{{selectedPage}}">
           <paper-icon-item>
             <iron-icon icon="device-emulator:volume-up" item-icon></iron-icon>
             Audio
           </paper-icon-item>
           <paper-icon-item>
             <iron-icon icon="device-emulator:battery-charging-full" item-icon>
             </iron-icon>
             Battery/Power
           </paper-icon-item>
           <paper-icon-item>
             <iron-icon icon="device-emulator:bluetooth" item-icon></iron-icon>
             Bluetooth
           </paper-icon-item>
+          <paper-icon-item>
+            <iron-icon icon="device-emulator:mouse" item-icon></iron-icon>
+            Input Devices
+          </paper-icon-item>
         </paper-listbox>
       </paper-header-panel>
       <paper-header-panel main class="flex layout vertical">
         <paper-toolbar>
           <paper-icon-button icon="device-emulator:menu" paper-drawer-toggle>
           </paper-icon-button>
           <header>Chrome OS Device Emulator</header>
         </paper-toolbar>
         <neon-animated-pages  class="fit" selected="[[selectedPage]]"
             entry-animation="fade-in-animation"
             exit-animation="fade-out-animation">
           <audio-settings id="audioSettings"></audio-settings>
           <battery-settings id="batterySettings"></battery-settings>
           <bluetooth-settings id="bluetoothSettings"></bluetooth-settings>
+          <input-device-settings id="inputDeviceSettings">
+          </input-device-settings>
         </neon-animated-pages>
       </paper-header-panel>
     </paper-drawer-panel>
   </template>
   <script src="device_emulator_pages.js"></script>
 </dom-module>