MD Settings: polish up some top-level buttons

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/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://md-settings/search_engines_page/search_engines_page.html">
 <link rel="import" href="chrome://md-settings/search_engines_page/search_engines_browser_proxy.html">
 <link rel="import" href="chrome://md-settings/settings_page/settings_animated_pages.html">
 <link rel="import" href="chrome://md-settings/settings_page/settings_subheader.html">
 <link rel="import" href="chrome://md-settings/settings_shared_css.html">
 
 <dom-module id="settings-search-page">
   <link rel="import" type="css" href="search_page.css">
   <template>
     <style include="settings-shared"></style>
     <settings-animated-pages id="pages" current-route="{{currentRoute}}"
         section="search">
       <neon-animatable id="main">
         <div class="settings-box first">
           <p class="start" i18n-content="searchExplanation"></p>
           <select id="searchEnginesMenu" on-change="onDefaultEngineChanged_">
             <template is="dom-repeat" items="[[searchEngines_]]">
               <option selected$="[[item.default]]" value="[[item.modelIndex]]">
                 [[item.name]]
               </option>
             </template>
           </select>
         </div>
         <div class="settings-box">
-          <paper-button class="link-button" i18n-content="searchEnginesManage"
-              on-tap="onManageSearchEnginesTap_">
+          <paper-button i18n-content="searchEnginesManage"
+              on-tap="onManageSearchEnginesTap_" class="primary-button">
           </paper-button>
         </div>
       </neon-animatable>
       <neon-animatable id="search-engines">
         <settings-subheader i18n-values="page-title:searchEnginesManage">
         </settings-subheader>
         <settings-search-engines-page></settings-search-engines-page>
       </neon-animatable>
     </settings-animated-pages>
   </template>
   <script src="search_page.js"></script>
 </dom-module>