MD-Settings: A11y - Label drop down menus.

chrome/browser/resources/settings/printing_page/cups_add_printer_dialog.html

 <link rel="import" href="chrome://resources/html/md_select_css.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-spinner/paper-spinner.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="cups_add_printer_dialog_util.html">
 <link rel="import" href="cups_printers_browser_proxy.html">
 <link rel="import" href="../settings_shared_css.html">
@@ skipping 150 matching lines @@
             <div class="secondary">
               <paper-input no-label-float id="printerAddressInput"
                   value="{{newPrinter.printerAddress}}"
                   on-input="onAddressChanged_">
               </paper-input>
             </div>
           </div>
         </div>
         <div class="settings-box two-line">
           <div class="start">
-            <div class="label">$i18n{printerProtocol}</div>
+            <div id="printerProtocol" class="label">$i18n{printerProtocol}</div>
             <div class="secondary">
               <div class="md-select-wrapper">
-                <select class="md-select" 
+                <select class="md-select" aria-labelledby="printerProtocol"
                     value="[[newPrinter.printerProtocol]]"
                     on-change="onProtocolChange_">
                   <option value="ipp">$i18n{printerProtocolIpp}</option>
                   <option value="ipps">$i18n{printerProtocolIpps}</option>
                   <option value="http">$i18n{printerProtocolHttp}</option>
                   <option value="https">$i18n{printerProtocolHttps}</option>
                   <option value="socket">$i18n{printerProtocolAppSocket}
                   </option>
                   <option value="lpd">$i18n{printerProtocolLpd}</option>
                 </select>
@@ skipping 201 matching lines @@
     <!-- Manufacturer and Model Dialog -->
     <template is="dom-if" if="[[showManufacturerDialog_]]" restamp>
       <add-printer-manufacturer-model-dialog new-printer="{{newPrinter}}"
           setup-failed="[[setupFailed]]">
       </add-printer-manufacturer-model-dialog>
     </template>
 
   </template>
   <script src="cups_add_printer_dialog.js"></script>
 </dom-module>