chrome/browser/resources/local_discovery/local_discovery.js - chromium/src - Git at Google

 // Copyright 2013 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.

 /**
  * Javascript for local_discovery.html, served from chrome://devices/
  * This is used to show discoverable devices near the user as well as
  * cloud devices registered to them.
  *
  * The object defined in this javascript file listens for callbacks from the
  * C++ code saying that a new device is available as well as manages the UI for
  * registering a device on the local network.
  */

 cr.define('local_discovery', function() {
   'use strict';

   // Histogram buckets for UMA tracking.
   /** @const */ var DEVICES_PAGE_EVENTS = {
     OPENED: 0,
     LOG_IN_STARTED_FROM_REGISTER_PROMO: 1,
     LOG_IN_STARTED_FROM_DEVICE_LIST_PROMO: 2,
     ADD_PRINTER_CLICKED: 3,
     REGISTER_CLICKED: 4,
     REGISTER_CONFIRMED: 5,
     REGISTER_SUCCESS: 6,
     REGISTER_CANCEL: 7,
     REGISTER_FAILURE: 8,
     MANAGE_CLICKED: 9,
     REGISTER_CANCEL_ON_PRINTER: 10,
     REGISTER_TIMEOUT: 11,
     LOG_IN_STARTED_FROM_REGISTER_OVERLAY_PROMO: 12,
     MAX_EVENT: 13,
   };

   /**
    * Map of service names to corresponding service objects.
    * @type {Object<string,Service>}
    */
   var devices = {};

   /**
    * Whether or not the user is currently logged in.
    * @type bool
    */
   var isUserLoggedIn = true;

   /**
    * Whether or not the user is supervised or off the record.
    * @type bool
    */
   var isUserSupervisedOrOffTheRecord = false;

   /**
    * Whether or not the path-based dialog has been shown.
    * @type bool
    */
   var dialogFromPathHasBeenShown = false;

   /**
    * Focus manager for page.
    */
   var focusManager = null;

   /**
    * Object that represents a device in the device list.
    * @param {Object} info Information about the device.
    * @constructor
    */
   function Device(info, registerEnabled) {
     this.info = info;
     this.domElement = null;
     this.registerButton = null;
     this.registerEnabled = registerEnabled;
   }

   Device.prototype = {
     /**
      * Update the device.
      * @param {Object} info New information about the device.
      */
     updateDevice: function(info) {
       this.info = info;
       this.renderDevice();
     },

     /**
      * Delete the device.
      */
     removeDevice: function() {
       this.deviceContainer().removeChild(this.domElement);
     },

     /**
      * Render the device to the device list.
      */
     renderDevice: function() {
       if (this.domElement) {
         clearElement(this.domElement);
       } else {
         this.domElement = document.createElement('div');
         this.deviceContainer().appendChild(this.domElement);
       }

       this.registerButton = fillDeviceDescription(
           this.domElement, this.info.display_name, this.info.description,
           this.info.type, loadTimeData.getString('serviceRegister'),
           this.showRegister.bind(this, this.info.type));

       this.setRegisterEnabled(this.registerEnabled);
     },

     /**
      * Return the correct container for the device.
      * @param {boolean} is_mine Whether or not the device is in the 'Registered'
      *    section.
      */
     deviceContainer: function() {
       return $('register-device-list');
     },

     /**
      * Register the device.
      */
     register: function() {
       recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CONFIRMED);
       chrome.send('registerDevice', [this.info.service_name]);
       setRegisterPage(
           isPrinter(this.info.type) ? 'register-printer-page-adding1' :
                                       'register-device-page-adding1');
     },
     /**
      * Show registrtation UI for device.
      */
     showRegister: function() {
       recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CLICKED);
       $('register-continue').onclick = this.register.bind(this);

       showRegisterOverlay();
     },
     /**
      * Set registration button enabled/disabled
      */
     setRegisterEnabled: function(isEnabled) {
       this.registerEnabled = isEnabled;
       if (this.registerButton) {
         this.registerButton.disabled = !isEnabled;
       }
     }
   };

   /**
    * Manages focus for local devices page.
    * @constructor
    * @extends {cr.ui.FocusManager}
    */
   function LocalDiscoveryFocusManager() {
     cr.ui.FocusManager.call(this);
     this.focusParent_ = document.body;
   }

   LocalDiscoveryFocusManager.prototype = {
     __proto__: cr.ui.FocusManager.prototype,
     /** @override */
     getFocusParent: function() {
       return document.querySelector('#overlay .showing') || $('main-page');
     }
   };

   /**
    * Returns a textual representation of the number of printers on the network.
    * @return {string} Number of printers on the network as localized string.
    */
   function generateNumberPrintersAvailableText(numberPrinters) {
     if (numberPrinters == 0) {
       return loadTimeData.getString('printersOnNetworkZero');
     } else if (numberPrinters == 1) {
       return loadTimeData.getString('printersOnNetworkOne');
     } else {
       return loadTimeData.getStringF(
           'printersOnNetworkMultiple', numberPrinters);
     }
   }

   /**
    * Fill device element with the description of a device.
    * @param {HTMLElement} device_dom_element Element to be filled.
    * @param {string} name Name of device.
    * @param {string} description Description of device.
    * @param {string} type Type of device.
    * @param {string} button_text Text to appear on button.
    * @param {function()?} button_action Action for button.
    * @return {HTMLElement} The button (for enabling/disabling/rebinding)
    */
   function fillDeviceDescription(
       device_dom_element, name, description, type, button_text, button_action) {
     device_dom_element.classList.add('device');
     if (isPrinter(type))
       device_dom_element.classList.add('printer');

     var deviceInfo = document.createElement('div');
     deviceInfo.className = 'device-info';
     device_dom_element.appendChild(deviceInfo);

     var deviceName = document.createElement('h3');
     deviceName.className = 'device-name';
     deviceName.textContent = name;
     deviceInfo.appendChild(deviceName);

     var deviceDescription = document.createElement('div');
     deviceDescription.className = 'device-subline';
     deviceDescription.textContent = description;
     deviceInfo.appendChild(deviceDescription);

     if (button_action) {
       var button = document.createElement('button');
       button.textContent = button_text;
       button.addEventListener('click', button_action);
       device_dom_element.appendChild(button);
     }

     return button;
   }

   /**
    * Show the register overlay.
    */
   function showRegisterOverlay() {
     recordUmaEvent(DEVICES_PAGE_EVENTS.ADD_PRINTER_CLICKED);

     var registerOverlay = $('register-overlay');
     registerOverlay.classList.add('showing');
     registerOverlay.focus();

     $('overlay').hidden = false;
     setRegisterPage('register-page-confirm');
   }

   /**
    * Hide the register overlay.
    */
   function hideRegisterOverlay() {
     $('register-overlay').classList.remove('showing');
     $('overlay').hidden = true;
   }

   /**
    * Clear a DOM element of all children.
    * @param {HTMLElement} element DOM element to clear.
    */
   function clearElement(element) {
     while (element.firstChild) {
       element.removeChild(element.firstChild);
     }
   }

   /**
    * Announce that a registration failed.
    */
   function onRegistrationFailed() {
     $('error-message').textContent =
         loadTimeData.getString('addingErrorMessage');
     setRegisterPage('register-page-error');
     recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_FAILURE);
   }

   /**
    * Announce that a registration has been canceled on the printer.
    */
   function onRegistrationCanceledPrinter() {
     $('error-message').textContent =
         loadTimeData.getString('addingCanceledMessage');
     setRegisterPage('register-page-error');
     recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CANCEL_ON_PRINTER);
   }

   /**
    * Announce that a registration has timed out.
    */
   function onRegistrationTimeout() {
     $('error-message').textContent =
         loadTimeData.getString('addingTimeoutMessage');
     setRegisterPage('register-page-error');
     recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_TIMEOUT);
   }

   /**
    * Update UI to reflect that registration has been confirmed on the printer.
    */
   function onRegistrationConfirmedOnPrinter() {
     setRegisterPage('register-printer-page-adding2');
   }

   /**
    * Shows UI to confirm security code.
    * @param {string} code The security code to confirm.
    */
   function onRegistrationConfirmDeviceCode(code) {
     setRegisterPage('register-device-page-adding2');
     $('register-device-page-code').textContent = code;
   }

   /**
    * Update device unregistered device list, and update related strings to
    * reflect the number of devices available to register.
    * @param {string} name Name of the device.
    * @param {string} info Additional info of the device or null if the device
    *                          has been removed.
    */
   function onUnregisteredDeviceUpdate(name, info) {
     if (info) {
       if (devices.hasOwnProperty(name)) {
         devices[name].updateDevice(info);
       } else {
         devices[name] = new Device(info, isUserLoggedIn);
         devices[name].renderDevice();
       }

       if (name == getOverlayIDFromPath() && !dialogFromPathHasBeenShown) {
         dialogFromPathHasBeenShown = true;
         devices[name].showRegister();
       }
     } else {
       if (devices.hasOwnProperty(name)) {
         devices[name].removeDevice();
         delete devices[name];
       }
     }

     updateUIToReflectState();
   }

   /**
    * Create the DOM for a cloud device described by the device section.
    * @param {Array<Object>} devices_list List of devices.
    */
   function createCloudDeviceDOM(device) {
     var devicesDomElement = document.createElement('div');

     var description;
     if (device.description == '') {
       if (isPrinter(device.type))
         description = loadTimeData.getString('noDescriptionPrinter');
       else
         description = loadTimeData.getString('noDescriptionDevice');
     } else {
       description = device.description;
     }

     fillDeviceDescription(
         devicesDomElement, device.display_name, description, device.type,
         loadTimeData.getString('manageDevice'),
         isPrinter(device.type) ? manageCloudDevice.bind(null, device.id) :
                                  null);
     return devicesDomElement;
   }

   /**
    * Handle a list of cloud devices available to the user globally.
    * @param {Array<Object>} devices_list List of devices.
    */
   function onCloudDeviceListAvailable(devices_list) {
     var devicesListLength = devices_list.length;
     var devicesContainer = $('cloud-devices');

     clearElement(devicesContainer);
     $('cloud-devices-loading').hidden = true;

     for (var i = 0; i < devicesListLength; i++) {
       devicesContainer.appendChild(createCloudDeviceDOM(devices_list[i]));
     }
   }

   /**
    * Handle the case where the list of cloud devices is not available.
    */
   function onCloudDeviceListUnavailable() {
     if (isUserLoggedIn) {
       $('cloud-devices-loading').hidden = true;
       $('cloud-devices-unavailable').hidden = false;
     }
   }

   /**
    * Handle the case where the cache for local devices has been flushed..
    */
   function onDeviceCacheFlushed() {
     for (var deviceName in devices) {
       devices[deviceName].removeDevice();
       delete devices[deviceName];
     }

     updateUIToReflectState();
   }

   /**
    * Update UI strings to reflect the number of local devices.
    */
   function updateUIToReflectState() {
     var numberPrinters = $('register-device-list').children.length;
     if (numberPrinters == 0) {
       $('no-printers-message').hidden = false;

       $('register-login-promo').hidden = true;
     } else {
       $('no-printers-message').hidden = true;
       $('register-login-promo').hidden =
           isUserLoggedIn || isUserSupervisedOrOffTheRecord;
     }
     if (!($('register-login-promo').hidden) ||
         !($('cloud-devices-login-promo').hidden) ||
         !($('register-overlay-login-promo').hidden)) {
       chrome.send(
           'metricsHandler:recordAction', ['Signin_Impression_FromDevicesPage']);
     }
   }

   /**
    * Announce that a registration succeeeded.
    */
   function onRegistrationSuccess(device_data) {
     hideRegisterOverlay();

     if (device_data.service_name == getOverlayIDFromPath()) {
       window.close();
     }

     var deviceDOM = createCloudDeviceDOM(device_data);
     $('cloud-devices').insertBefore(deviceDOM, $('cloud-devices').firstChild);
     recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_SUCCESS);
   }

   /**
    * Update visibility status for page.
    */
   function updateVisibility() {
     chrome.send('isVisible', [!document.hidden]);
   }

   /**
    * Set the page that the register wizard is on.
    * @param {string} page_id ID string for page.
    */
   function setRegisterPage(page_id) {
     var pages = $('register-overlay').querySelectorAll('.register-page');
     var pagesLength = pages.length;
     for (var i = 0; i < pagesLength; i++) {
       pages[i].hidden = true;
     }

     $(page_id).hidden = false;
   }

   /**
    * Request the device list.
    */
   function requestDeviceList() {
     if (isUserLoggedIn) {
       clearElement($('cloud-devices'));
       $('cloud-devices-loading').hidden = false;
       $('cloud-devices-unavailable').hidden = true;

       chrome.send('requestDeviceList');
     }
   }

   /**
    * Go to management page for a cloud device.
    * @param {string} device_id ID of device.
    */
   function manageCloudDevice(device_id) {
     recordUmaEvent(DEVICES_PAGE_EVENTS.MANAGE_CLICKED);
     chrome.send('openCloudPrintURL', [device_id]);
   }

   /**
    * Record an event in the UMA histogram.
    * @param {number} eventId The id of the event to be recorded.
    * @private
    */
   function recordUmaEvent(eventId) {
     chrome.send(
         'metricsHandler:recordInHistogram',
         ['LocalDiscovery.DevicesPage', eventId, DEVICES_PAGE_EVENTS.MAX_EVENT]);
   }

   /**
    * Cancel the registration.
    */
   function cancelRegistration() {
     hideRegisterOverlay();
     chrome.send('cancelRegistration');
     recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CANCEL);
   }

   /**
    * Confirms device code.
    */
   function confirmCode() {
     chrome.send('confirmCode');
     setRegisterPage('register-device-page-adding1');
   }

   /**
    * Retry loading the devices from Google Cloud Print.
    */
   function retryLoadCloudDevices() {
     requestDeviceList();
   }

   /**
    * User is not logged in.
    */
   function setUserLoggedIn(userLoggedIn, userSupervisedOrOffTheRecord) {
     isUserLoggedIn = userLoggedIn;
     isUserSupervisedOrOffTheRecord = userSupervisedOrOffTheRecord;

     $('cloud-devices-login-promo').hidden =
         isUserLoggedIn || isUserSupervisedOrOffTheRecord;
     $('register-overlay-login-promo').hidden =
         isUserLoggedIn || isUserSupervisedOrOffTheRecord;
     $('register-continue').disabled =
         !isUserLoggedIn || isUserSupervisedOrOffTheRecord;

     $('my-devices-container').hidden = userSupervisedOrOffTheRecord;

     if (isUserSupervisedOrOffTheRecord) {
       $('cloud-print-connector-section').hidden = true;
     }

     if (isUserLoggedIn && !isUserSupervisedOrOffTheRecord) {
       requestDeviceList();
       $('register-login-promo').hidden = true;
     } else {
       $('cloud-devices-loading').hidden = true;
       $('cloud-devices-unavailable').hidden = true;
       clearElement($('cloud-devices'));
       hideRegisterOverlay();
     }

     updateUIToReflectState();

     for (var device in devices) {
       devices[device].setRegisterEnabled(isUserLoggedIn);
     }
   }

   function openSignInPage() {
     chrome.send('showSyncUI');
   }

   function registerLoginButtonClicked() {
     recordUmaEvent(DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_REGISTER_PROMO);
     openSignInPage();
   }

   function registerOverlayLoginButtonClicked() {
     recordUmaEvent(
         DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_REGISTER_OVERLAY_PROMO);
     openSignInPage();
   }

   function cloudDevicesLoginButtonClicked() {
     recordUmaEvent(DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_DEVICE_LIST_PROMO);
     openSignInPage();
   }

   /**
    * Set the Cloud Print proxy UI to enabled, disabled, or processing.
    * @private
    */
   function setupCloudPrintConnectorSection(disabled, label, allowed) {
     if (!cr.isChromeOS) {
       $('cloudPrintConnectorLabel').textContent = label;
       if (disabled || !allowed) {
         $('cloudPrintConnectorSetupButton').textContent =
             loadTimeData.getString('cloudPrintConnectorDisabledButton');
       } else {
         $('cloudPrintConnectorSetupButton').textContent =
             loadTimeData.getString('cloudPrintConnectorEnabledButton');
       }
       $('cloudPrintConnectorSetupButton').disabled = !allowed;

       if (disabled) {
         $('cloudPrintConnectorSetupButton').onclick = function(event) {
           // Disable the button, set its text to the intermediate state.
           $('cloudPrintConnectorSetupButton').textContent =
               loadTimeData.getString('cloudPrintConnectorEnablingButton');
           $('cloudPrintConnectorSetupButton').disabled = true;
           chrome.send('showCloudPrintSetupDialog');
         };
       } else {
         $('cloudPrintConnectorSetupButton').onclick = function(event) {
           chrome.send('disableCloudPrintConnector');
           requestDeviceList();
         };
       }
     }
   }

   function getOverlayIDFromPath() {
     if (document.location.pathname == '/register') {
       var params = parseQueryParams(document.location);
       return params['id'] || null;
     }
   }

   /**
    * Returns true of device is printer.
    * @param {string} type Type of printer.
    */
   function isPrinter(type) {
     return type == 'printer';
   }

   document.addEventListener('DOMContentLoaded', function() {
     cr.ui.overlay.setupOverlay($('overlay'));
     cr.ui.overlay.globalInitialization();
     $('overlay').addEventListener('cancelOverlay', cancelRegistration);

     [].forEach.call(
         document.querySelectorAll('.register-cancel'), function(button) {
           button.addEventListener('click', cancelRegistration);
         });

     [].forEach.call(
         document.querySelectorAll('.confirm-code'), function(button) {
           button.addEventListener('click', confirmCode);
         });

     $('register-error-exit').addEventListener('click', cancelRegistration);


     $('cloud-devices-retry-link')
         .addEventListener('click', retryLoadCloudDevices);

     $('cloud-devices-login-link')
         .addEventListener('click', cloudDevicesLoginButtonClicked);

     $('register-login-link')
         .addEventListener('click', registerLoginButtonClicked);

     $('register-overlay-login-button')
         .addEventListener('click', registerOverlayLoginButtonClicked);

     if (loadTimeData.valueExists('backButtonURL')) {
       $('back-link').hidden = false;
       $('back-link').addEventListener('click', function() {
         window.location.href = loadTimeData.getString('backButtonURL');
       });
     }

     updateVisibility();
     document.addEventListener('visibilitychange', updateVisibility, false);

     focusManager = new LocalDiscoveryFocusManager();
     focusManager.initialize();

     chrome.send('start');
     recordUmaEvent(DEVICES_PAGE_EVENTS.OPENED);
   });

   return {
     onRegistrationSuccess: onRegistrationSuccess,
     onRegistrationFailed: onRegistrationFailed,
     onUnregisteredDeviceUpdate: onUnregisteredDeviceUpdate,
     onRegistrationConfirmedOnPrinter: onRegistrationConfirmedOnPrinter,
     onRegistrationConfirmDeviceCode: onRegistrationConfirmDeviceCode,
     onCloudDeviceListAvailable: onCloudDeviceListAvailable,
     onCloudDeviceListUnavailable: onCloudDeviceListUnavailable,
     onDeviceCacheFlushed: onDeviceCacheFlushed,
     onRegistrationCanceledPrinter: onRegistrationCanceledPrinter,
     onRegistrationTimeout: onRegistrationTimeout,
     setUserLoggedIn: setUserLoggedIn,
     setupCloudPrintConnectorSection: setupCloudPrintConnectorSection,
   };
 });
	// Copyright 2013 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.

	/**
	* Javascript for local_discovery.html, served from chrome://devices/
	* This is used to show discoverable devices near the user as well as
	* cloud devices registered to them.
	*
	* The object defined in this javascript file listens for callbacks from the
	* C++ code saying that a new device is available as well as manages the UI for
	* registering a device on the local network.
	*/

	cr.define('local_discovery', function() {
	'use strict';

	// Histogram buckets for UMA tracking.
	/** @const */ var DEVICES_PAGE_EVENTS = {
	OPENED: 0,
	LOG_IN_STARTED_FROM_REGISTER_PROMO: 1,
	LOG_IN_STARTED_FROM_DEVICE_LIST_PROMO: 2,
	ADD_PRINTER_CLICKED: 3,
	REGISTER_CLICKED: 4,
	REGISTER_CONFIRMED: 5,
	REGISTER_SUCCESS: 6,
	REGISTER_CANCEL: 7,
	REGISTER_FAILURE: 8,
	MANAGE_CLICKED: 9,
	REGISTER_CANCEL_ON_PRINTER: 10,
	REGISTER_TIMEOUT: 11,
	LOG_IN_STARTED_FROM_REGISTER_OVERLAY_PROMO: 12,
	MAX_EVENT: 13,
	};

	/**
	* Map of service names to corresponding service objects.
	* @type {Object<string,Service>}
	*/
	var devices = {};

	/**
	* Whether or not the user is currently logged in.
	* @type bool
	*/
	var isUserLoggedIn = true;

	/**
	* Whether or not the user is supervised or off the record.
	* @type bool
	*/
	var isUserSupervisedOrOffTheRecord = false;

	/**
	* Whether or not the path-based dialog has been shown.
	* @type bool
	*/
	var dialogFromPathHasBeenShown = false;

	/**
	* Focus manager for page.
	*/
	var focusManager = null;

	/**
	* Object that represents a device in the device list.
	* @param {Object} info Information about the device.
	* @constructor
	*/
	function Device(info, registerEnabled) {
	this.info = info;
	this.domElement = null;
	this.registerButton = null;
	this.registerEnabled = registerEnabled;
	}

	Device.prototype = {
	/**
	* Update the device.
	* @param {Object} info New information about the device.
	*/
	updateDevice: function(info) {
	this.info = info;
	this.renderDevice();
	},

	/**
	* Delete the device.
	*/
	removeDevice: function() {
	this.deviceContainer().removeChild(this.domElement);
	},

	/**
	* Render the device to the device list.
	*/
	renderDevice: function() {
	if (this.domElement) {
	clearElement(this.domElement);
	} else {
	this.domElement = document.createElement('div');
	this.deviceContainer().appendChild(this.domElement);
	}

	this.registerButton = fillDeviceDescription(
	this.domElement, this.info.display_name, this.info.description,
	this.info.type, loadTimeData.getString('serviceRegister'),
	this.showRegister.bind(this, this.info.type));

	this.setRegisterEnabled(this.registerEnabled);
	},

	/**
	* Return the correct container for the device.
	* @param {boolean} is_mine Whether or not the device is in the 'Registered'
	* section.
	*/
	deviceContainer: function() {
	return $('register-device-list');
	},

	/**
	* Register the device.
	*/
	register: function() {
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CONFIRMED);
	chrome.send('registerDevice', [this.info.service_name]);
	setRegisterPage(
	isPrinter(this.info.type) ? 'register-printer-page-adding1' :
	'register-device-page-adding1');
	},
	/**
	* Show registrtation UI for device.
	*/
	showRegister: function() {
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CLICKED);
	$('register-continue').onclick = this.register.bind(this);

	showRegisterOverlay();
	},
	/**
	* Set registration button enabled/disabled
	*/
	setRegisterEnabled: function(isEnabled) {
	this.registerEnabled = isEnabled;
	if (this.registerButton) {
	this.registerButton.disabled = !isEnabled;
	}
	}
	};

	/**
	* Manages focus for local devices page.
	* @constructor
	* @extends {cr.ui.FocusManager}
	*/
	function LocalDiscoveryFocusManager() {
	cr.ui.FocusManager.call(this);
	this.focusParent_ = document.body;
	}

	LocalDiscoveryFocusManager.prototype = {
	__proto__: cr.ui.FocusManager.prototype,
	/** @override */
	getFocusParent: function() {
	return document.querySelector('#overlay .showing') \|\| $('main-page');
	}
	};

	/**
	* Returns a textual representation of the number of printers on the network.
	* @return {string} Number of printers on the network as localized string.
	*/
	function generateNumberPrintersAvailableText(numberPrinters) {
	if (numberPrinters == 0) {
	return loadTimeData.getString('printersOnNetworkZero');
	} else if (numberPrinters == 1) {
	return loadTimeData.getString('printersOnNetworkOne');
	} else {
	return loadTimeData.getStringF(
	'printersOnNetworkMultiple', numberPrinters);
	}
	}

	/**
	* Fill device element with the description of a device.
	* @param {HTMLElement} device_dom_element Element to be filled.
	* @param {string} name Name of device.
	* @param {string} description Description of device.
	* @param {string} type Type of device.
	* @param {string} button_text Text to appear on button.
	* @param {function()?} button_action Action for button.
	* @return {HTMLElement} The button (for enabling/disabling/rebinding)
	*/
	function fillDeviceDescription(
	device_dom_element, name, description, type, button_text, button_action) {
	device_dom_element.classList.add('device');
	if (isPrinter(type))
	device_dom_element.classList.add('printer');

	var deviceInfo = document.createElement('div');
	deviceInfo.className = 'device-info';
	device_dom_element.appendChild(deviceInfo);

	var deviceName = document.createElement('h3');
	deviceName.className = 'device-name';
	deviceName.textContent = name;
	deviceInfo.appendChild(deviceName);

	var deviceDescription = document.createElement('div');
	deviceDescription.className = 'device-subline';
	deviceDescription.textContent = description;
	deviceInfo.appendChild(deviceDescription);

	if (button_action) {
	var button = document.createElement('button');
	button.textContent = button_text;
	button.addEventListener('click', button_action);
	device_dom_element.appendChild(button);
	}

	return button;
	}

	/**
	* Show the register overlay.
	*/
	function showRegisterOverlay() {
	recordUmaEvent(DEVICES_PAGE_EVENTS.ADD_PRINTER_CLICKED);

	var registerOverlay = $('register-overlay');
	registerOverlay.classList.add('showing');
	registerOverlay.focus();

	$('overlay').hidden = false;
	setRegisterPage('register-page-confirm');
	}

	/**
	* Hide the register overlay.
	*/
	function hideRegisterOverlay() {
	$('register-overlay').classList.remove('showing');
	$('overlay').hidden = true;
	}

	/**
	* Clear a DOM element of all children.
	* @param {HTMLElement} element DOM element to clear.
	*/
	function clearElement(element) {
	while (element.firstChild) {
	element.removeChild(element.firstChild);
	}
	}

	/**
	* Announce that a registration failed.
	*/
	function onRegistrationFailed() {
	$('error-message').textContent =
	loadTimeData.getString('addingErrorMessage');
	setRegisterPage('register-page-error');
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_FAILURE);
	}

	/**
	* Announce that a registration has been canceled on the printer.
	*/
	function onRegistrationCanceledPrinter() {
	$('error-message').textContent =
	loadTimeData.getString('addingCanceledMessage');
	setRegisterPage('register-page-error');
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CANCEL_ON_PRINTER);
	}

	/**
	* Announce that a registration has timed out.
	*/
	function onRegistrationTimeout() {
	$('error-message').textContent =
	loadTimeData.getString('addingTimeoutMessage');
	setRegisterPage('register-page-error');
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_TIMEOUT);
	}

	/**
	* Update UI to reflect that registration has been confirmed on the printer.
	*/
	function onRegistrationConfirmedOnPrinter() {
	setRegisterPage('register-printer-page-adding2');
	}

	/**
	* Shows UI to confirm security code.
	* @param {string} code The security code to confirm.
	*/
	function onRegistrationConfirmDeviceCode(code) {
	setRegisterPage('register-device-page-adding2');
	$('register-device-page-code').textContent = code;
	}

	/**
	* Update device unregistered device list, and update related strings to
	* reflect the number of devices available to register.
	* @param {string} name Name of the device.
	* @param {string} info Additional info of the device or null if the device
	* has been removed.
	*/
	function onUnregisteredDeviceUpdate(name, info) {
	if (info) {
	if (devices.hasOwnProperty(name)) {
	devices[name].updateDevice(info);
	} else {
	devices[name] = new Device(info, isUserLoggedIn);
	devices[name].renderDevice();
	}

	if (name == getOverlayIDFromPath() && !dialogFromPathHasBeenShown) {
	dialogFromPathHasBeenShown = true;
	devices[name].showRegister();
	}
	} else {
	if (devices.hasOwnProperty(name)) {
	devices[name].removeDevice();
	delete devices[name];
	}
	}

	updateUIToReflectState();
	}

	/**
	* Create the DOM for a cloud device described by the device section.
	* @param {Array<Object>} devices_list List of devices.
	*/
	function createCloudDeviceDOM(device) {
	var devicesDomElement = document.createElement('div');

	var description;
	if (device.description == '') {
	if (isPrinter(device.type))
	description = loadTimeData.getString('noDescriptionPrinter');
	else
	description = loadTimeData.getString('noDescriptionDevice');
	} else {
	description = device.description;
	}

	fillDeviceDescription(
	devicesDomElement, device.display_name, description, device.type,
	loadTimeData.getString('manageDevice'),
	isPrinter(device.type) ? manageCloudDevice.bind(null, device.id) :
	null);
	return devicesDomElement;
	}

	/**
	* Handle a list of cloud devices available to the user globally.
	* @param {Array<Object>} devices_list List of devices.
	*/
	function onCloudDeviceListAvailable(devices_list) {
	var devicesListLength = devices_list.length;
	var devicesContainer = $('cloud-devices');

	clearElement(devicesContainer);
	$('cloud-devices-loading').hidden = true;

	for (var i = 0; i < devicesListLength; i++) {
	devicesContainer.appendChild(createCloudDeviceDOM(devices_list[i]));
	}
	}

	/**
	* Handle the case where the list of cloud devices is not available.
	*/
	function onCloudDeviceListUnavailable() {
	if (isUserLoggedIn) {
	$('cloud-devices-loading').hidden = true;
	$('cloud-devices-unavailable').hidden = false;
	}
	}

	/**
	* Handle the case where the cache for local devices has been flushed..
	*/
	function onDeviceCacheFlushed() {
	for (var deviceName in devices) {
	devices[deviceName].removeDevice();
	delete devices[deviceName];
	}

	updateUIToReflectState();
	}

	/**
	* Update UI strings to reflect the number of local devices.
	*/
	function updateUIToReflectState() {
	var numberPrinters = $('register-device-list').children.length;
	if (numberPrinters == 0) {
	$('no-printers-message').hidden = false;

	$('register-login-promo').hidden = true;
	} else {
	$('no-printers-message').hidden = true;
	$('register-login-promo').hidden =
	isUserLoggedIn \|\| isUserSupervisedOrOffTheRecord;
	}
	if (!($('register-login-promo').hidden) \|\|
	!($('cloud-devices-login-promo').hidden) \|\|
	!($('register-overlay-login-promo').hidden)) {
	chrome.send(
	'metricsHandler:recordAction', ['Signin_Impression_FromDevicesPage']);
	}
	}

	/**
	* Announce that a registration succeeeded.
	*/
	function onRegistrationSuccess(device_data) {
	hideRegisterOverlay();

	if (device_data.service_name == getOverlayIDFromPath()) {
	window.close();
	}

	var deviceDOM = createCloudDeviceDOM(device_data);
	$('cloud-devices').insertBefore(deviceDOM, $('cloud-devices').firstChild);
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_SUCCESS);
	}

	/**
	* Update visibility status for page.
	*/
	function updateVisibility() {
	chrome.send('isVisible', [!document.hidden]);
	}

	/**
	* Set the page that the register wizard is on.
	* @param {string} page_id ID string for page.
	*/
	function setRegisterPage(page_id) {
	var pages = $('register-overlay').querySelectorAll('.register-page');
	var pagesLength = pages.length;
	for (var i = 0; i < pagesLength; i++) {
	pages[i].hidden = true;
	}

	$(page_id).hidden = false;
	}

	/**
	* Request the device list.
	*/
	function requestDeviceList() {
	if (isUserLoggedIn) {
	clearElement($('cloud-devices'));
	$('cloud-devices-loading').hidden = false;
	$('cloud-devices-unavailable').hidden = true;

	chrome.send('requestDeviceList');
	}
	}

	/**
	* Go to management page for a cloud device.
	* @param {string} device_id ID of device.
	*/
	function manageCloudDevice(device_id) {
	recordUmaEvent(DEVICES_PAGE_EVENTS.MANAGE_CLICKED);
	chrome.send('openCloudPrintURL', [device_id]);
	}

	/**
	* Record an event in the UMA histogram.
	* @param {number} eventId The id of the event to be recorded.
	* @private
	*/
	function recordUmaEvent(eventId) {
	chrome.send(
	'metricsHandler:recordInHistogram',
	['LocalDiscovery.DevicesPage', eventId, DEVICES_PAGE_EVENTS.MAX_EVENT]);
	}

	/**
	* Cancel the registration.
	*/
	function cancelRegistration() {
	hideRegisterOverlay();
	chrome.send('cancelRegistration');
	recordUmaEvent(DEVICES_PAGE_EVENTS.REGISTER_CANCEL);
	}

	/**
	* Confirms device code.
	*/
	function confirmCode() {
	chrome.send('confirmCode');
	setRegisterPage('register-device-page-adding1');
	}

	/**
	* Retry loading the devices from Google Cloud Print.
	*/
	function retryLoadCloudDevices() {
	requestDeviceList();
	}

	/**
	* User is not logged in.
	*/
	function setUserLoggedIn(userLoggedIn, userSupervisedOrOffTheRecord) {
	isUserLoggedIn = userLoggedIn;
	isUserSupervisedOrOffTheRecord = userSupervisedOrOffTheRecord;

	$('cloud-devices-login-promo').hidden =
	isUserLoggedIn \|\| isUserSupervisedOrOffTheRecord;
	$('register-overlay-login-promo').hidden =
	isUserLoggedIn \|\| isUserSupervisedOrOffTheRecord;
	$('register-continue').disabled =
	!isUserLoggedIn \|\| isUserSupervisedOrOffTheRecord;

	$('my-devices-container').hidden = userSupervisedOrOffTheRecord;

	if (isUserSupervisedOrOffTheRecord) {
	$('cloud-print-connector-section').hidden = true;
	}

	if (isUserLoggedIn && !isUserSupervisedOrOffTheRecord) {
	requestDeviceList();
	$('register-login-promo').hidden = true;
	} else {
	$('cloud-devices-loading').hidden = true;
	$('cloud-devices-unavailable').hidden = true;
	clearElement($('cloud-devices'));
	hideRegisterOverlay();
	}

	updateUIToReflectState();

	for (var device in devices) {
	devices[device].setRegisterEnabled(isUserLoggedIn);
	}
	}

	function openSignInPage() {
	chrome.send('showSyncUI');
	}

	function registerLoginButtonClicked() {
	recordUmaEvent(DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_REGISTER_PROMO);
	openSignInPage();
	}

	function registerOverlayLoginButtonClicked() {
	recordUmaEvent(
	DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_REGISTER_OVERLAY_PROMO);
	openSignInPage();
	}

	function cloudDevicesLoginButtonClicked() {
	recordUmaEvent(DEVICES_PAGE_EVENTS.LOG_IN_STARTED_FROM_DEVICE_LIST_PROMO);
	openSignInPage();
	}

	/**
	* Set the Cloud Print proxy UI to enabled, disabled, or processing.
	* @private
	*/
	function setupCloudPrintConnectorSection(disabled, label, allowed) {
	if (!cr.isChromeOS) {
	$('cloudPrintConnectorLabel').textContent = label;
	if (disabled \|\| !allowed) {
	$('cloudPrintConnectorSetupButton').textContent =
	loadTimeData.getString('cloudPrintConnectorDisabledButton');
	} else {
	$('cloudPrintConnectorSetupButton').textContent =
	loadTimeData.getString('cloudPrintConnectorEnabledButton');
	}
	$('cloudPrintConnectorSetupButton').disabled = !allowed;

	if (disabled) {
	$('cloudPrintConnectorSetupButton').onclick = function(event) {
	// Disable the button, set its text to the intermediate state.
	$('cloudPrintConnectorSetupButton').textContent =
	loadTimeData.getString('cloudPrintConnectorEnablingButton');
	$('cloudPrintConnectorSetupButton').disabled = true;
	chrome.send('showCloudPrintSetupDialog');
	};
	} else {
	$('cloudPrintConnectorSetupButton').onclick = function(event) {
	chrome.send('disableCloudPrintConnector');
	requestDeviceList();
	};
	}
	}
	}

	function getOverlayIDFromPath() {
	if (document.location.pathname == '/register') {
	var params = parseQueryParams(document.location);
	return params['id'] \|\| null;
	}
	}

	/**
	* Returns true of device is printer.
	* @param {string} type Type of printer.
	*/
	function isPrinter(type) {
	return type == 'printer';
	}

	document.addEventListener('DOMContentLoaded', function() {
	cr.ui.overlay.setupOverlay($('overlay'));
	cr.ui.overlay.globalInitialization();
	$('overlay').addEventListener('cancelOverlay', cancelRegistration);

	[].forEach.call(
	document.querySelectorAll('.register-cancel'), function(button) {
	button.addEventListener('click', cancelRegistration);
	});

	[].forEach.call(
	document.querySelectorAll('.confirm-code'), function(button) {
	button.addEventListener('click', confirmCode);
	});

	$('register-error-exit').addEventListener('click', cancelRegistration);


	$('cloud-devices-retry-link')
	.addEventListener('click', retryLoadCloudDevices);

	$('cloud-devices-login-link')
	.addEventListener('click', cloudDevicesLoginButtonClicked);

	$('register-login-link')
	.addEventListener('click', registerLoginButtonClicked);

	$('register-overlay-login-button')
	.addEventListener('click', registerOverlayLoginButtonClicked);

	if (loadTimeData.valueExists('backButtonURL')) {
	$('back-link').hidden = false;
	$('back-link').addEventListener('click', function() {
	window.location.href = loadTimeData.getString('backButtonURL');
	});
	}

	updateVisibility();
	document.addEventListener('visibilitychange', updateVisibility, false);

	focusManager = new LocalDiscoveryFocusManager();
	focusManager.initialize();

	chrome.send('start');
	recordUmaEvent(DEVICES_PAGE_EVENTS.OPENED);
	});

	return {
	onRegistrationSuccess: onRegistrationSuccess,
	onRegistrationFailed: onRegistrationFailed,
	onUnregisteredDeviceUpdate: onUnregisteredDeviceUpdate,
	onRegistrationConfirmedOnPrinter: onRegistrationConfirmedOnPrinter,
	onRegistrationConfirmDeviceCode: onRegistrationConfirmDeviceCode,
	onCloudDeviceListAvailable: onCloudDeviceListAvailable,
	onCloudDeviceListUnavailable: onCloudDeviceListUnavailable,
	onDeviceCacheFlushed: onDeviceCacheFlushed,
	onRegistrationCanceledPrinter: onRegistrationCanceledPrinter,
	onRegistrationTimeout: onRegistrationTimeout,
	setUserLoggedIn: setUserLoggedIn,
	setupCloudPrintConnectorSection: setupCloudPrintConnectorSection,
	};
	});