[i18n] use Polymer data binding to change locale strings

chrome/browser/resources/chromeos/login/oobe_welcome.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.
 
 /**
  * @fileoverview Polymer element for displaying material design OOBE.
  */
 
 Polymer({
   is: 'oobe-welcome-md',
@@ skipping 14 matching lines @@
       type: String,
       value: '',
     },
 
     /**
      * List of languages for language selector dropdown.
      * @type {!Array<OobeTypes.LanguageDsc>}
      */
     languages: {
       type: Array,
-      observer: "onLanguagesChanged_",
+      observer: 'onLanguagesChanged_',
     },
 
     /**
      * List of keyboards for keyboard selector dropdown.
      * @type {!Array<OobeTypes.IMEDsc>}
      */
     keyboards: {
       type: Array,
-      observer: "onKeyboardsChanged_",
+      observer: 'onKeyboardsChanged_',
     },
 
     /**
      * Flag that enables MD-OOBE.
      */
     enabled: {
       type: Boolean,
       value: false,
     },
 
@@ skipping 15 matching lines @@
     },
 
     /**
      * If UI uses forced keyboard navigation.
      */
     highlightStrength: {
       type: String,
       value: '',
     },
 
+    /*
+     * Signal dynamic language change.
+     * Note: the type and value are arbitrary, but the value does need to change
+     * to cause a str('...', i18n_) update.
+     * @private
+     */
+    i18n_: {
+      type: Number,
+      value: 0,
+    },
+
     /**
      * True when connected to a network.
      * @private
      */
     isConnected_: {
       type: Boolean,
       value: false,
     },
 
     /**
      * Controls displaying of "Enable debugging features" link.
      */
-     debuggingLinkVisible: Boolean,
+    debuggingLinkVisible: Boolean,
   },
 
   /**
    * GUID of the user-selected network. It is remembered after user taps on
    * network entry. After we receive event "connected" on this network,
    * OOBE will proceed.
    */
   networkLastSelectedGuid_: '',
 
   /** @override */
@@ skipping 20 matching lines @@
       networkListItemNotConnected:
           loadTimeData.getString('networkListItemNotConnected'),
       vpnNameTemplate: loadTimeData.getString('vpnNameTemplate'),
 
       // Additional strings for custom items.
       addMobileNetworkMenuName:
           loadTimeData.getString('addMobileNetworkMenuName'),
       addWiFiNetworkMenuName: loadTimeData.getString('addWiFiNetworkMenuName'),
       proxySettingsMenuName: loadTimeData.getString('proxySettingsMenuName'),
     };
+
+    this.set('i18n_', this.i18n_ + 1);

[Alexander Alekseev, 2017/05/20 01:21:12]

I don't like the idea of per-screen JS depencence.

This particular screen object has updateLocalizedContent() call for a very
special reason: it is using "special" cr-network-list element that requires this
ugly code.

UI objects should not have explicit updateLocalizedContent() methods. We can
hide them in behavior, but I don't like the idea of explicit
updateLocalizedContent() in every object.

[dschuyler, 2017/05/20 01:44:48]

I agree that it is not pretty, but it's a special case (changing the language a
page is displayed in without reloading the page). I think oobe and login are the
corner case rather than the common case (and for that reason I believe that
special casing here is appropriate).

[Alexander Alekseev, 2017/05/20 01:50:57]

I believe that OOBE/Login is likely a half of Chrome OS UI.
(It also includes a lot of chrome://settings code).

Could you wrap it all into a polymer behavior?

[Dan Beam, 2017/05/20 02:03:29]

i don't know how a behavior would help that the binding syntax needs something
that changes to re-run

[Dan Beam, 2017/05/20 02:03:29]

fwiw: this could also just be

this.i18n_++;

[Alexander Alekseev, 2017/05/20 02:25:21]

updateLocalizedContent should go into the behavior.
Behaviors can have properties.

Also I posted this above: http://stackoverflow.com/a/31129122 .

[dschuyler, 2017/05/23 00:03:18]

Acknowledged.

[dschuyler, 2017/05/23 00:03:18]

Acknowledged.

[dschuyler, 2017/05/23 00:03:18]

I'd like that (moving the existing code) to be a separate CL.

[dschuyler, 2017/05/23 00:03:18]

Done.

   },
 
   /**
    * Hides all screens to help switching from one screen to another.
    * @private
    */
   hideAllScreens_: function() {
     this.$.welcomeScreen.hidden = true;
 
-    var screens = Polymer.dom(this.root).querySelectorAll('oobe-dialog')
+    var screens = Polymer.dom(this.root).querySelectorAll('oobe-dialog');
     for (var i = 0; i < screens.length; ++i) {
       screens[i].hidden = true;
     }
   },
 
   /**
    * Shows given screen.
    * @param id String Screen ID.
    * @private
    */
   showScreen_: function(id) {
     this.hideAllScreens_();
 
     var screen = this.$[id];
     assert(screen);
     screen.hidden = false;
     screen.show();
   },
 
   /**
+   * Get the i18n string for the given tag.
+   * @return {string}
+   * @private
+   */
+  str_: function(tag) {
+    return loadTimeData.getString(tag);
+  },
+
+  /**
    * Returns active screen object.
    * @private
    */
   getActiveScreen_: function() {
-    var screens = Polymer.dom(this.root).querySelectorAll('oobe-dialog')
+    var screens = Polymer.dom(this.root).querySelectorAll('oobe-dialog');
     for (var i = 0; i < screens.length; ++i) {
       if (!screens[i].hidden)
         return screens[i];
     }
     return this.$.welcomeScreen;
   },
 
   focus: function() {
     this.getActiveScreen_().focus();
   },
@@ skipping 22 matching lines @@
    * when connected to a network.
    * @private
    */
   getNetworkCustomItems_: function(isConnected_) {
     var self = this;
     var items = [
       {
         customItemName: 'proxySettingsMenuName',
         polymerIcon: 'oobe-welcome-20:add-proxy',
         customData: {
-          onTap: function() { self.OpenProxySettingsDialog_(); },
+          onTap: function() {
+            self.OpenProxySettingsDialog_();
+          },
         },
       },
       {
         customItemName: 'addWiFiNetworkMenuName',
         polymerIcon: 'oobe-welcome-20:add-wifi',
         customData: {
-          onTap: function() { self.OpenAddWiFiNetworkDialog_(); },
+          onTap: function() {
+            self.OpenAddWiFiNetworkDialog_();
+          },
         },
       },
       {
         customItemName: 'addMobileNetworkMenuName',
         polymerIcon: 'oobe-welcome-20:add-cellular',
         customData: {
-          onTap: function() { self.OpenAddWiFiNetworkDialog_(); },
+          onTap: function() {
+            self.OpenAddWiFiNetworkDialog_();
+          },
         },
       },
     ];
     if (isConnected_)
       return items;
     return items.slice(1);
   },
 
   /**
    * Returns true if timezone button should be visible.
@@ skipping 33 matching lines @@
   /**
    * Handle "Timezone" button for "Welcome" screen.
    *
    * @private
    */
   onWelcomeTimezoneButtonClicked_: function() {
     this.showScreen_('timezoneScreen');
   },
 
   /**
-   * Handle Networwork Setup screen "Proxy settings" button.
+   * Handle Network Setup screen "Proxy settings" button.
    *
    * @private
    */
   OpenProxySettingsDialog_: function(item) {
     chrome.send('launchProxySettingsDialog');
   },
 
   /**
-   * Handle Networwork Setup screen "Add WiFi network" button.
+   * Handle Network Setup screen "Add WiFi network" button.
    *
    * @private
    */
   OpenAddWiFiNetworkDialog_: function(item) {
     chrome.send('launchAddWiFiNetworkDialog');
   },
 
   /**
-   * Handle Networwork Setup screen "Add cellular network" button.
+   * Handle Network Setup screen "Add cellular network" button.
    *
    * @private
    */
   OpenAddMobileNetworkDialog_: function(item) {
     chrome.send('launchAddMobileNetworkDialog');
   },
 
   /**
    * This is called when network setup is done.
    *
@@ skipping 180 matching lines @@
    * @private
    */
   onTimezoneSelected_: function(event) {
     var item = event.detail;
     if (!item)
       return;
 
     this.screen.onTimezoneSelected_(item.value);
   },
 });