Settings: Implement sub-subpages, and clean up some animations.

chrome/browser/resources/settings/search_page/search_page.html

 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/more-routing/more-routing.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/cr_elements/v1_0/cr_button/cr_button.html">
 <link rel="import" href="chrome://md-settings/checkbox/checkbox.html">
 <link rel="import" href="chrome://md-settings/search_engines_page/search_engines_page.html">
 <link rel="import" href="chrome://md-settings/settings_page/settings_animated_pages.html">
 
 <dom-module id="cr-settings-search-page">
   <link rel="import" type="css"
       href="chrome://md-settings/settings_page/settings_page.css">
   <link rel="import" type="css" href="search_page.css">
   <template>
     <cr-settings-animated-pages id="pages" in-subpage="{{inSubpage}}">
       <neon-animatable id="main">
         <p i18n-content="searchExplanation"></p>
 
         <div class="search-engines">
           <select id="searchEnginesMenu" on-change="defaultEngineGuidChanged_">
             <template is="dom-repeat" items="[[searchEngines]]">
               <option value="[[item.guid]]">{{item.name}}</option>
             </template>
           </select>
 
-          <cr-button class="manage-search-engines"
+          <cr-button class="search-engines"
               i18n-content="searchManageButtonLabel"
-              on-click="manageSearchEngines_" raised>
+              on-tap="onSearchEnginesTap_" raised>
           </cr-button>
         </div>
       </neon-animatable>
       <neon-animatable id="search-engines">
         <div class="subheader">
-          <paper-icon-button icon="arrow-back" on-tap="handleBack_">
+          <paper-icon-button icon="arrow-back" on-tap="onBackTap_">
           </paper-icon-button>
           <h2 i18n-content="searchEnginesLabel"></h2>
         </div>
         <cr-settings-search-engines-page></cr-settings-search-engines-page>
+        <cr-button class="search-engines-subpage"
+            i18n-content="advancedPageTitle"
+            on-tap="onSearchEnginesSubpageTap_" raised>
+        </cr-button>
+      </neon-animatable>
+      <neon-animatable id="search-engines-subpage">
+        <!-- This sub-subpage is purely a placeholder to provide an example. -->
+        <div class="subheader">
+          <paper-icon-button icon="arrow-back" on-tap="onBackTap_">
+          </paper-icon-button>
+          <h2 i18n-content="searchEnginesLabel"></h2>
+        </div>
+        <p i18n-content="searchExplanation"></p>
       </neon-animatable>
     </cr-settings-animated-pages>
   </template>
   <script src="search_page.js"></script>
 </dom-module>