Improve ChromeVox experience for OS settings Language page

There are three main changes needed to improve the ChromeVox experience for the
settings OS language page:

-Apply aria-hidden to the language labels to remove them from ChromeVox
 navigation. Instead only navigate to the associated buttons

-When a user chooses a language to display the system text in, a Restart button
 is displayed on the screen. That Restart button needs a label to better
 describe/announce its purpose.

-Each item in the "Input method" keyboard list used two ChromeVox navigation
 stops instead of one. Applying aria-hidden to the inner div then aria-label to
 the outer div fixed this behavior

Screen captures:
Before: https://bugs.chromium.org/p/chromium/issues/detail?id=976452#c15
After: https://bugs.chromium.org/p/chromium/issues/detail?id=976452#c16

Bug: 976452
Change-Id: I90a70f3c4197a3b0f6eea3f8696d36766eba373d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1952091
Commit-Queue: Gavin Williams <gavinwill@chromium.org>
Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723548}

chrome/app/settings_strings.grdp

@@ -2880,6 +2880,9 @@
     <message name="IDS_SETTINGS_LANGUAGES_DISPLAY_IN_THIS_LANGUAGE" desc="The label used for a button that changes the UI language.">
       Show system text in this language
     </message>
+    <message name="IDS_SETTINGS_LANGUAGES_RESTART_TO_DISPLAY_LANGUAGE" desc="The aria label to be read aloud to describe a button for restarting the device to change the device's UI language.">
+      Restart device to show system text in <ph name="LANGUAGE">$1<ex>English</ex></ph>
+    </message>
   </if>
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_LANGUAGES_LANGUAGES_LIST_ORDERING_INSTRUCTIONS" desc="Explanatory message about ordering the list of languages.">

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

@@ -155,7 +155,8 @@
         <template is="dom-repeat" items="[[languages.enabled]]">
           <div class$="list-item [[getLanguageItemClass_(
               item.language.code, language.prospectiveUILanguage)]]">
-            <div class="start">
+            <div class="start" id="displayText-[[index]]"
+                aria-hidden="true">
               <div title="[[item.language.nativeDisplayName]]">
                 [[item.language.displayName]]
               </div>
@@ -169,13 +170,17 @@
             <template is="dom-if" if="[[isRestartRequired_(
                 item.language.code, languages.prospectiveUILanguage)]]"
                 restamp>
-              <cr-button id="restartButton" on-click="onRestartTap_">
+              <cr-button id="restartButton" on-click="onRestartTap_"
+                  aria-label$="[[getRestartButtonDescription_(
+                      item.language.displayName)]]">
                 $i18n{restart}
               </cr-button>
             </template>
             <cr-icon-button class="icon-more-vert"
                 title="$i18n{moreActions}" id="more-[[item.language.code]]"
-                on-click="onDotsTap_"></cr-icon-button>
+                on-click="onDotsTap_"
+                aria-labelledby$="displayText-[[index]]">
+            </cr-icon-button>
           </div>
         </template>
         <div class="list-item">
@@ -197,8 +202,9 @@
               actionable on-click="onInputMethodTap_"
               on-keypress="onInputMethodTap_" on-mousedown="onMouseDown_"
               tabindex$="[[getInputMethodTabIndex_(
-                  item.id, languages.inputMethods.currentId)]]">
-            <div class="start">
+                  item.id, languages.inputMethods.currentId)]]"
+              aria-labelledby$="language-[[index]]" role="button">
+            <div class="start" id="language-[[index]]" aria-hidden="true">
               <div class="display-name">[[item.displayName]]</div>
               <div class="explain-selected"
                   hidden="[[!isCurrentInputMethod_(

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

@@ -495,5 +495,14 @@ Polymer({
     // Preventing the mousedown event from propagating prevents focus being set.
     e.preventDefault();
   },
+
+  /**
+   * @param {string} language The language displayed in the row
+   * @return {string}
+   * @private
+   */
+  getRestartButtonDescription_: function(language) {
+    return this.i18n('displayLanguageRestart', language);
+  },
 });
 })();

chrome/browser/ui/webui/settings/settings_localized_strings_provider.cc

@@ -1660,6 +1660,8 @@ void AddLanguagesStrings(content::WebUIDataSource* html_source) {
     {"manageInputMethodsPageTitle",
      IDS_SETTINGS_LANGUAGES_MANAGE_INPUT_METHODS_TITLE},
     {"showImeMenu", IDS_SETTINGS_LANGUAGES_SHOW_IME_MENU},
+    {"displayLanguageRestart",
+     IDS_SETTINGS_LANGUAGES_RESTART_TO_DISPLAY_LANGUAGE},
 #endif
     {"addLanguagesDialogTitle", IDS_SETTINGS_LANGUAGES_MANAGE_LANGUAGES_TITLE},
     {"allLanguages", IDS_SETTINGS_LANGUAGES_ALL_LANGUAGES},