[MD settings] removing secondary-button class

chrome/browser/resources/settings/about_page/about_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="about_page_browser_proxy.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../lifetime_browser_proxy.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_page/main_page_behavior.html">
 <link rel="import" href="../settings_page/settings_animated_pages.html">
 <link rel="import" href="../settings_page/settings_section.html">
 <link rel="import" href="../settings_page_css.html">
@@ skipping 109 matching lines @@
                     hidden="[[!obsoleteSystemInfo_.obsolete]]">
                   $i18n{aboutObsoleteSystem}
                   <a href="$i18n{aboutObsoleteSystemURL}" target="_blank">
                     $i18n{learnMore}
                   </a>
                 </span>
                 <div class="secondary copyable">$i18n{aboutBrowserVersion}</div>
               </div>
               <div class="separator" hidden="[[!showButtonContainer_]]"></div>
               <span id="buttonContainer" hidden="[[!showButtonContainer_]]">
-                <paper-button id="relaunch" class="secondary-button"
-                    hidden="[[!showRelaunch_]]" on-tap="onRelaunchTap_">
+                <paper-button id="relaunch" hidden="[[!showRelaunch_]]"
+                    on-tap="onRelaunchTap_">
                   $i18n{aboutRelaunch}
                 </paper-button>
 <if expr="chromeos">
-                <paper-button id="relaunchAndPowerwash" class="secondary-button"
+                <paper-button id="relaunchAndPowerwash"
                     hidden="[[!showRelaunchAndPowerwash_]]"
                     on-tap="onRelaunchAndPowerwashTap_">
                   $i18n{aboutRelaunchAndPowerwash}
                 </paper-button>
-                <paper-button id="checkForUpdates" class="secondary-button"
+                <paper-button id="checkForUpdates"
                     hidden="[[!showCheckUpdates_]]"
                     on-tap="onCheckUpdatesTap_">
                   $i18n{aboutCheckForUpdates}
                 </paper-button>
 </if>
               </span>
             </div>
 <if expr="_google_chrome and is_macosx">
             <template is="dom-if" if="[[!promoteUpdaterStatus_.hidden]]">
               <div id="promoteUpdater" class="settings-box"
@@ skipping 75 matching lines @@
 <if expr="chromeos">
     <template is="dom-if" if="[[showUpdateWarningDialog_]]" restamp>
       <settings-update-warning-dialog update-info="[[updateInfo_]]"
           on-close="onUpdateWarningDialogClose_">
       </settings-update-warning-dialog>
     </template>
 </if>
   </template>
   <script src="about_page.js"></script>
 </dom-module>