MD Settings: Network a11y fixes

chrome/browser/resources/settings/internet_page/network_proxy.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_behavior.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_indicator.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.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/polymer/v1_0/iron-a11y-keys/iron-a11y-keys.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-container.html">
@@ skipping 74 matching lines @@
       </settings-toggle-button>
     </div>
 
     <!-- Proxy type dropdown -->
     <div class="settings-box continuation indent">
       <div class="start">$i18n{networkProxyConnectionType}</div>
       <div class="md-select-wrapper">
         <select id="proxyType" class="md-select" on-change="onTypeChange_"
             value="[[proxy_.Type]]"
             disabled="[[!isEditable_('Type', networkProperties, editable,
-                useSharedProxies_)]]">
+                useSharedProxies_)]]"
+            aria-label="$i18n{networkProxyConnectionType}">
           <template is="dom-repeat" items="[[proxyTypes_]]">
             <option value="[[item]]">[[getProxyTypeDesc_(item)]]</option>
           </template>
         </select>
         <span class="md-select-underline"></span>
       </div>
     </div>
 
     <!-- Autoconfiguration (PAC) -->
     <div class="settings-box continuation indent"
@@ skipping 108 matching lines @@
         </paper-button>
         <paper-button class="action-button"
             on-tap="onAllowSharedDialogConfirm_">
           $i18n{confirm}
         </paper-button>
       </div>
     </dialog>
   </template>
   <script src="network_proxy.js"></script>
 </dom-module>