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

chrome/browser/resources/settings/device_page/keyboard.html

Index: chrome/browser/resources/settings/device_page/keyboard.html
diff --git a/chrome/browser/resources/settings/device_page/keyboard.html b/chrome/browser/resources/settings/device_page/keyboard.html
index 075525a7adcdd58166ffd9d7436e74d0a6b19d21..b57ec09c6360deb02e1dfc2a596e9e926bd6a85d 100644
--- a/chrome/browser/resources/settings/device_page/keyboard.html
+++ b/chrome/browser/resources/settings/device_page/keyboard.html
@@ -109,11 +109,13 @@
     <div id="keyboardOverlay" class="settings-box"
         on-tap="onShowKeyboardShortcutsOverlayTap_" actionable>
       <div class="start">$i18n{showKeyboardShortcutsOverlay}</div>
-      <button class="icon-external" is="paper-icon-button-light"></button>
+      <button class="icon-external" is="paper-icon-button-light"
+          aria-label="$i18n{showKeyboardShortcutsOverlay}"></button>
     </div>
     <div class="settings-box" on-tap="onShowLanguageInputTap_" actionable>
       <div class="start">$i18n{keyboardShowLanguageAndInput}</div>
-      <button class="subpage-arrow" is="paper-icon-button-light"></button>
+      <button class="subpage-arrow" is="paper-icon-button-light"
+          aria-label="$i18n{keyboardShowLanguageAndInput}"></button>
     </div>
   </template>
   <script src="keyboard.js"></script>