MD Settings: Fix paper/iron dropdown alignment

chrome/browser/resources/settings/controls/settings_dropdown_menu.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-dropdown-menu/paper-dropdown-menu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-listbox/paper-listbox.html">
 <link rel="import" href="/controls/pref_control_behavior.html">
 <link rel="import" href="/i18n_setup.html">
 <link rel="import" href="/prefs/pref_util.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="settings-dropdown-menu">
   <template>
     <style include="settings-shared">
     </style>
     <paper-dropdown-menu id="dropdownMenu" label="[[menuLabel_]]"
+        vertical-align="auto"
         on-iron-select="onSelect_" no-label-float$="[[noLabelFloat]]"
         disabled="[[shouldDisableMenu_(disabled, menuOptions.*)]]">
       <paper-listbox class="dropdown-content" selected="{{selected_}}"
           attr-for-selected="data-value">
         <template is="dom-repeat" items="[[menuOptions]]" initial-count="5">
           <button class="dropdown-item" role="option"
               data-value$="[[item.value]]">
             [[item.name]]
           </button>
         </template>
         <button class="dropdown-item" role="option"
             data-value$="[[notFoundValue_]]"
             hidden$="[[!isSelectedNotFound_(selected_)]]">
           $i18n{custom}
         </button>
       </paper-listbox>
     </paper-dropdown-menu>
   </template>
   <script src="settings_dropdown_menu.js"></script>
 </dom-module>