MD Settings: label and describe a bunch of subpage/open-in-new buttons

chrome/browser/resources/settings/a11y_page/manage_a11y_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_shared_css.html">
 <link rel="import" href="../settings_vars_css.html">
 
 <dom-module id="settings-manage-a11y-page">
   <template>
@@ skipping 23 matching lines @@
       </span>
     </div>
 
     <h2>$i18n{textToSpeechHeading}</h2>
     <div class="settings-box first" actionable>
       <settings-toggle-button class="start"
           pref="{{prefs.settings.accessibility}}"
           label="$i18n{chromeVoxLabel}">
         <button class="more-actions icon-external" is="paper-icon-button-light"
             on-tap="onChromeVoxSettingsTap_"
-            hidden="[[!prefs.settings.accessibility.value]]"></button>
+            hidden="[[!prefs.settings.accessibility.value]]"
+            aria-label="$i18n{chromeVoxLabel}"></button>
       </settings-toggle-button>
     </div>
     <template is="dom-if" if="[[showExperimentalFeatures_]]">
       <div class="settings-box block">
         <settings-toggle-button
             pref="{{prefs.settings.a11y.select_to_speak}}"
             label="$i18n{selectToSpeakTitle}"
             sub-label="$i18n{selectToSpeakDescription}">
         </settings-toggle-button>
       </div>
     </template>
 
     <h2>$i18n{displayHeading}</h2>
     <div class="settings-box block first">
       <settings-toggle-button
           pref="{{prefs.settings.a11y.high_contrast_enabled}}"
           label="$i18n{highContrastLabel}">
       </settings-toggle-button>
       <settings-toggle-button
           pref="{{prefs.settings.a11y.screen_magnifier}}"
           label="$i18n{screenMagnifierLabel}">
       </settings-toggle-button>
     </div>
     <div class="settings-box two-line" on-tap="onDisplayTap_" actionable>
       <div class="start">
         $i18n{displaySettingsTitle}
-        <div class="secondary">$i18n{displaySettingsDescription}</div>
+        <div class="secondary" id="deisplaySettingsSecondary">
+          $i18n{displaySettingsDescription}
+        </div>
       </div>
-      <button class="subpage-arrow" is="paper-icon-button-light"></button>
+      <button class="subpage-arrow" is="paper-icon-button-light"
+          aria-label="$i18n{displaySettingsTitle}"
+          aria-describedby="displaySettingsSecondary"></button>
     </div>
     <div class="settings-box two-line" on-tap="onAppearanceTap_" actionable>
       <div class="start">
         $i18n{appearanceSettingsTitle}
-        <div class="secondary">$i18n{appearanceSettingsDescription}</div>
+        <div class="secondary" id="appearanceSettingsSecondary">
+          $i18n{appearanceSettingsDescription}
+        </div>
       </div>
-      <button class="subpage-arrow" is="paper-icon-button-light"></button>
+      <button class="subpage-arrow" is="paper-icon-button-light"
+          aria-label="$i18n{appearanceSettingsTitle}"
+          aria-describedby="appearanceSettingsSecondary"></button>
     </div>
 
     <h2>$i18n{keyboardHeading}</h2>
     <div class="settings-box block first">
       <settings-toggle-button
           pref="{{prefs.settings.a11y.sticky_keys_enabled}}"
           label="$i18n{stickyKeysLabel}">
       </settings-toggle-button>
       <settings-toggle-button
           pref="{{prefs.settings.a11y.virtual_keyboard}}"
@@ skipping 10 matching lines @@
       <template is="dom-if" if="[[showExperimentalFeatures_]]">
         <settings-toggle-button
             pref="{{prefs.settings.a11y.switch_access}}"
             label="$i18n{switchAccessLabel}">
         </settings-toggle-button>
       </template>
     </div>
     <div class="settings-box two-line" on-tap="onKeyboardTap_" actionable>
       <div class="start">
         $i18n{keyboardSettingsTitle}
-        <div class="secondary">$i18n{keyboardSettingsDescription}</div>
+        <div class="secondary" id="keyboardSettingsSecondary">
+          $i18n{keyboardSettingsDescription}
+        </div>
       </div>
-      <button class="subpage-arrow" is="paper-icon-button-light"></button>
+      <button class="subpage-arrow" is="paper-icon-button-light"
+          aria-label="$i18n{keyboardSettingsTitle}"
+          aria-describedby="keyboardSettingsSecondary"></button>
     </div>
 
     <h2>$i18n{mouseAndTouchpadHeading}</h2>
     <div class="settings-box block first">
       <settings-toggle-button
           pref="{{prefs.settings.a11y.autoclick}}"
           label="$i18n{clickOnStopLabel}">
       </settings-toggle-button>
       <div class="list-item settings-toggle-button-spacer">
         <div>$i18n{delayBeforeClickLabel}</div>
@@ skipping 12 matching lines @@
           label="$i18n{largeMouseCursorLabel}">
       </settings-toggle-button>
       <settings-toggle-button
           pref="{{prefs.settings.a11y.cursor_highlight}}"
           label="$i18n{cursorHighlightLabel}">
       </settings-toggle-button>
     </div>
     <div class="settings-box two-line" on-tap="onMouseTap_" actionable>
       <div class="start">
         $i18n{mouseSettingsTitle}
-        <div class="secondary">$i18n{mouseSettingsDescription}</div>
+        <div class="secondary" id="mouseSettingsSecondary">
+          $i18n{mouseSettingsDescription}
+        </div>
       </div>
-      <button class="subpage-arrow" is="paper-icon-button-light"></button>
+      <button class="subpage-arrow" is="paper-icon-button-light"
+          aria-label="$i18n{mouseSettingsTitle}"
+          aria-describedby="mouseSettingsSecondary"></button>
     </div>
 
     <h2>$i18n{audioHeading}</h2>
     <div class="settings-box block first">
       <settings-toggle-button
           pref="{{prefs.settings.a11y.mono_audio}}"
           label="$i18n{monoAudioLabel}">
       </settings-toggle-button>
     </div>
 
     <div class="settings-box two-line" on-tap="onMoreFeaturesTap_" actionable>
       <div class="start">
         $i18n{additionalFeaturesTitle}
-        <div class="secondary">$i18n{a11yWebStore}</div>
+        <div class="secondary" id="moreFeaturesSecondary">
+          $i18n{a11yWebStore}
+        </div>
       </div>
-      <button class="icon-external" is="paper-icon-button-light"></button>
+      <button class="icon-external" is="paper-icon-button-light"
+          aria-label="$i18n{additionalFeaturesTitle}"
+          aria-describedby="moreFeaturesSecondary"></button>
     </div>
   </template>
   <script src="manage_a11y_page.js"></script>
 </dom-module>