MD Settings: Bluetooth: Add a11y label for toggle button

chrome/browser/resources/settings/bluetooth_page/bluetooth_page.html

 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_indicator.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../prefs/prefs.html">
@@ skipping 20 matching lines @@
               pref="[[prefs.cros.device.allow_bluetooth]]"
             hidden="[[prefs.cros.device.allow_bluetooth.value]]">
           </cr-policy-pref-indicator>
           <button class="subpage-arrow" is="paper-icon-button-light"
               on-tap="onSubpageArrowTap_" aria-label="$i18n{bluetoothPageTitle}"
               aria-describedby="bluetoothSecondary">
           </button>
           <div class="secondary-action">
             <paper-toggle-button id="enableBluetooth"
                 checked="{{bluetoothEnabled_}}"
-                disabled="[[!adapterState_.available]]" on-tap="stopTap_">
+                disabled="[[!adapterState_.available]]" on-tap="stopTap_"
+                aria-label="$i18n{bluetoothToggleA11yLabel}">
             </paper-toggle-button>
           </div>
         </div>
       </neon-animatable>
 
       <template is="dom-if" route-path="/bluetoothDevices">
         <settings-subpage associated-control="[[$$('#bluetoothDevices')]]"
             page-title="$i18n{bluetoothPageTitle}">
           <settings-bluetooth-subpage 
               adapter-state="[[adapterState_]]"
               bluetooth-enabled="{{bluetoothEnabled_}}"
               bluetooth="[[bluetooth]]"
               bluetooth-private="[[bluetoothPrivate]]">
           </settings-bluetooth-subpage>
         </settings-subpage>
       </template>
 
     </settings-animated-pages>
   </template>
   <script src="bluetooth_page.js"></script>
 </dom-module>