[OsSettingsLanguages] Add screen reader message for selecting language

Screenreader screenshot selected: http://screen/53h3eMnL8RTELzi
Screenreader screenshot not selected: http://screen/9h78tbAmL6tbqSB

Bug: 1113439
Change-Id: I2f2bf3c8e7f08de4050eb54883ef07764d5bbc71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418528
Commit-Queue: My Nguyen <myy@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809055}

chrome/app/os_settings_strings.grdp

@@ -265,6 +265,12 @@
   <message name="IDS_OS_SETTINGS_LANGUAGES_CHANGE_DEVICE_LANGUAGE_DIALOG_DESCRIPTION" desc="Description for the dialog to change device language.">
     You need to restart your Chromebook to change the device language. <ph name="BEGIN_LINK_LEARN_MORE">&lt;a target="_blank" href="$1"&gt;</ph>Learn more<ph name="END_LINK_LEARN_MORE">&lt;/a&gt;</ph>
   </message>
+  <message name="IDS_OS_SETTINGS_LANGUAGES_SELECTED_DEVICE_LANGUAGE_INSTRUCTION" desc="Instruction read by screen reader when users can unselect a language.">
+    <ph name="LANGUAGE">$1<ex>English</ex></ph> selected. Press Search plus Space to unselect.
+  </message>
+  <message name="IDS_OS_SETTINGS_LANGUAGES_NOT_SELECTED_DEVICE_LANGUAGE_INSTRUCTION" desc="Instruction read by screen reader when users can select a language.">
+    <ph name="LANGUAGE">$1<ex>English</ex></ph> not selected. Press Search plus Space to select.
+  </message>
   <message name="IDS_OS_SETTINGS_LANGUAGES_CHANGE_DEVICE_LANGUAGE_CONFIRM_BUTTON_LABEL" desc="Label for the button where users can confirm the selected language and restart the device.">
     Confirm and restart
   </message>

chrome/app/os_settings_strings_grdp/IDS_OS_SETTINGS_LANGUAGES_NOT_SELECTED_DEVICE_LANGUAGE_INSTRUCTION.png.sha1

+1f20d267ac05e7ce369e92a0ff663dc786933106
\ No newline at end of file

chrome/app/os_settings_strings_grdp/IDS_OS_SETTINGS_LANGUAGES_SELECTED_DEVICE_LANGUAGE_INSTRUCTION.png.sha1

+07c1ace900a98f51b82c89a5f084887ed75a081a
\ No newline at end of file

chrome/browser/resources/settings/chromeos/os_languages_page/change_device_language_dialog.html

@@ -82,9 +82,10 @@
           <template>
             <!-- |selected| is a property of iron-list -->
             <div class$="list-item [[getItemClass_(selected)]]"
-                tabindex$="[[tabIndex]]">
+                tabindex$="[[tabIndex]]"
+                aria-label="[[getAriaLabelForItem_(item, selected)]]">
               <paper-ripple></paper-ripple>
-              <div class="flex padded">
+              <div class="flex padded" aria-hidden="true">
                 [[getDisplayText_(item)]]
               </div>
               <iron-icon icon="settings:check-circle" hidden="[[!selected]]">

chrome/browser/resources/settings/chromeos/os_languages_page/change_device_language_dialog.js

@@ -76,6 +76,18 @@ Polymer({
     return selected ? 'selected' : '';
   },
 
+  /**
+   * @param {!chrome.languageSettingsPrivate.Language} item
+   * @param {boolean} selected
+   * @return {!string}
+   * @private
+   */
+  getAriaLabelForItem_(item, selected) {
+    const instruction = selected ? 'selectedDeviceLanguageInstruction' :
+                                   'notSelectedDeviceLanguageInstruction';
+    return this.i18n(instruction, this.getDisplayText_(item));
+  },
+
   /**
    * @param {!chrome.languageSettingsPrivate.Language} language
    * @return {string} The text to be displayed.

chrome/browser/ui/webui/settings/chromeos/languages_section.cc

@@ -276,6 +276,10 @@ void AddLanguagesPageStringsV2(content::WebUIDataSource* html_source) {
        IDS_OS_SETTINGS_LANGUAGES_OFFER_TRANSLATION_SUBLABEL},
       {"changeDeviceLanguageDialogTitle",
        IDS_OS_SETTINGS_LANGUAGES_CHANGE_DEVICE_LANGUAGE_DIALOG_TITLE},
+      {"selectedDeviceLanguageInstruction",
+       IDS_OS_SETTINGS_LANGUAGES_SELECTED_DEVICE_LANGUAGE_INSTRUCTION},
+      {"notSelectedDeviceLanguageInstruction",
+       IDS_OS_SETTINGS_LANGUAGES_NOT_SELECTED_DEVICE_LANGUAGE_INSTRUCTION},
       {"changeDeviceLanguageConfirmButtonLabel",
        IDS_OS_SETTINGS_LANGUAGES_CHANGE_DEVICE_LANGUAGE_CONFIRM_BUTTON_LABEL},
   };