[MD settings] change button padding and placement

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

 <link rel="import" href="chrome://resources/html/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://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="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_subpage.html">
 <link rel="import" href="chrome://md-settings/settings_shared_css.html">
@@ skipping 36 matching lines @@
           <paper-dropdown-menu>
             <paper-listbox class="dropdown-content"
                 selected="[[getSelectedSearchEngineIndex_(searchEngines_)]]"
                 on-iron-select="onIronSelect_">
               <template is="dom-repeat" items="[[searchEngines_]]">
                 <div>[[item.name]]</div>
               </template>
             </paper-listbox>
           </paper-dropdown-menu>
         </div>
-        <div class="settings-box">
+        <div class="settings-box button-strip">
           <paper-button on-tap="onManageSearchEnginesTap_"
               class="primary-button">
             $i18n{searchEnginesManage}
           </paper-button>
         </div>
       </neon-animatable>
       <template is="dom-if" name="search-engines">
         <settings-subpage page-title="$i18n{searchEnginesManage}">
           <settings-search-engines-page></settings-search-engines-page>
         </settings-subpage>
       </template>
     </settings-animated-pages>
   </template>
   <script src="search_page.js"></script>
 </dom-module>