[MD settings] change button padding and placement

chrome/browser/resources/settings/privacy_page/privacy_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.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/clear_browsing_data_dialog/clear_browsing_data_dialog.html">
 <link rel="import" href="chrome://md-settings/controls/settings_checkbox.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">
 <link rel="import" href="chrome://md-settings/site_settings/all_sites.html">
@@ skipping 82 matching lines @@
 </if>
         <div class="settings-box two-line" on-tap="onSiteSettingsTap_">
           <div class="start">
             <div>$i18n{siteSettings}</div>
             <div class="secondary">
               <!-- TODO(dschuyler): replace this placeholder text -->
               Contrary to popular belief, Lorem Ipsum is not simply random text.
             </div>
           </div>
         </div>
-        <div class="settings-box">
+        <div class="settings-box button-strip">
           <paper-button on-tap="onClearBrowsingDataTap_" class="primary-button">
             $i18n{clearBrowsingData}
           </paper-button>
         </div>
       </neon-animatable>
 <if expr="use_nss_certs">
       <template is="dom-if" name="manage-certificates">
         <settings-subpage page-title="$i18n{manageCertificates}">
           <settings-certificate-manager-page>
           </settings-certificate-manager-page>
@@ skipping 106 matching lines @@
       <template is="dom-if" name="site-details">
         <settings-subpage
             page-title="$i18n{siteSettingsSiteDetailsPageTitle}">
           <site-details site="[[selectedSite]]"></site-details>
         </settings-subpage>
       </template>
     </settings-animated-pages>
   </template>
   <script src="privacy_page.js"></script>
 </dom-module>