MD Settings: Debounce navigation event in side nav.

chrome/browser/resources/settings/settings_menu/settings_menu.html

 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-selector/iron-selector.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_shared_css.html">
@@ skipping 115 matching lines @@
         $i18n{onStartup}
       </a>
       <paper-button toggles id="advancedButton"
           aria-active-attribute="aria-expanded" active="{{advancedOpened}}"
           hidden="[[!pageVisibility.advancedSettings]]">
         <span>$i18n{advancedPageTitle}</span>
         <iron-icon icon="[[arrowState_(advancedOpened)]]">
         </iron-icon></paper-button>
       <iron-collapse id="advancedSubmenu" opened="[[advancedOpened]]"
           hidden="[[!pageVisibility.advancedSettings]]">
-        <iron-selector id="subMenu" selectable="a" attr-for-selected="href"
-            on-iron-activate="onSelectorActivate_">
+        <iron-selector id="subMenu" selectable="a" attr-for-selected="href">
 <if expr="chromeos">
           <a href="/dateTime">
             <iron-icon icon="settings:access-time"></iron-icon>
             $i18n{dateTimePageTitle}
           </a>
 </if>
           <a href="/privacy">
             <iron-icon icon="settings:security"></iron-icon>
             $i18n{privacyPageTitle}
           </a>
@@ skipping 29 matching lines @@
             $i18n{resetPageTitle}
           </a>
         </iron-selector>
       </iron-collapse>
       <div class="separator"></div>
       <a id="about-menu" href="/help">$i18n{aboutPageTitle}</a>
     </iron-selector>
   </template>
   <script src="settings_menu.js"></script>
 </dom-module>