Enable a11y audit for chrome://settings

chrome/browser/resources/options/content_settings.html

 <div id="content-settings-page" class="page" hidden>
   <div class="close-button"></div>
   <h1 i18n-content="contentSettingsPage"></h1>
   <div class="content-area">
     <!-- Cookie filter tab contents -->
     <section>
       <h3 i18n-content="cookiesTabLabel"></h3>
       <div class="replace-with-website-settings">
         <div class="radio controlled-setting-with-label">
           <label>
@@ skipping 423 matching lines @@
 </if>
     <!-- Media Stream capture device filter -->
     <section id="media-stream-settings">
       <div class="section-header">
         <h3 i18n-content="mediaStreamTabLabel"></h3>
         <span id="media-indicator"
             class="controlled-setting-indicator group-indicator"></span>
       </div>
       <div>
         <div class="media-device-control">
-          <span i18n-content="mediaSelectMicLabel"></span>
-          <select id="media-select-mic" class="weakrtl"></select>
+          <span id="media-select-mic-label" i18n-content="mediaSelectMicLabel">
+          </span>
+          <select id="media-select-mic" class="weakrtl"
+                  aria-labelledby="media-select-mic-label"></select>
         </div>
         <div class="media-device-control">
-          <span i18n-content="mediaSelectCameraLabel"></span>
-          <select id="media-select-camera" class="weakrtl"></select>
+          <span id="media-select-camera-label"
+                i18n-content="mediaSelectCameraLabel"></span>
+          <select id="media-select-camera" class="weakrtl"
+                  aria-labelledby="media-select-camera-label"></select>
         </div>
         <div class="radio controlled-setting-with-label">
           <label>
             <input type="radio" name="media-stream" value="ask">
             <span>
               <span id="media-stream-ask-label" i18n-content="mediaStreamAsk">
               </span>
               <span class="controlled-setting-indicator"
                   content-setting="media-stream" value="ask"></span>
             </span>
@@ skipping 178 matching lines @@
     </section>
   </div>
   <div class="action-area">
     <div class="button-strip">
       <button id="content-settings-overlay-confirm" class="default-button"
           i18n-content="done">
       </button>
     </div>
   </div>
 </div>