MD Settings: Update Bluetooth toggle UI to match spec.

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

 <link rel="import" href="chrome://resources/cr_elements/cr_scrollable_behavior.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/iron-list/iron-list.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-spinner/paper-spinner.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../settings_shared_css.html">
 <link rel="import" href="bluetooth_device_dialog.html">
 <link rel="import" href="bluetooth_device_list_item.html">
 
 <dom-module id="settings-bluetooth-subpage">
   <template>
     <style include="settings-shared">
       .container {
         @apply(--settings-list-frame-padding);
         min-height: 10px;
         overflow-y: auto;
       }
 
       .header {
         margin-top: 10px;
       }
 
       paper-spinner {
         @apply(--cr-icon-height-width);
       }
+
+      #onoff[on] {
+        color: var(--settings-toggle-color);
+      }
     </style>
 
     <div class="settings-box first">
-      <div class="start">[[getOffOnString_(bluetoothEnabled)]]</div>
+      <div id="onoff" class="start" on$="[[bluetoothEnabled]]">
+        [[getOnOffString_(bluetoothEnabled,
+          '$i18nPolymer{deviceOn}', '$i18nPolymer{deviceOff}')]]
+      </div>
       <paper-toggle-button id="enableBluetooth" checked="{{bluetoothEnabled}}"
           aria-label="$i18n{bluetoothToggleA11yLabel}">
       </paper-toggle-button>
     </div>
 
     <!-- Paired device list -->
     <div class="settings-box first header" hidden$="[[!bluetoothEnabled]]">
       <div class="start">$i18n{bluetoothDeviceListPaired}</div>
     </div>
     <div id="noPairedDevices" class="list-frame"
@@ skipping 45 matching lines @@
         dialog-id="[[dialogId_]]"
         error-message="[[errorMessage_]]"
         on-close="onDialogClosed_"
         on-device-event="onDeviceEvent_"
         pairing-device="[[pairingDevice_]]">
     </bluetooth-device-dialog>
 
   </template>
   <script src="bluetooth_subpage.js"></script>
 </dom-module>