Old and new about pages: simplify product logo animation code

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

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="/about_page/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 17 matching lines @@
       .copyable {
         -webkit-user-select: text;
       }
 
       .product-title {
         font-size: 20px;
         margin-bottom: auto;
         margin-top: auto;
       }
 
-      @-webkit-keyframes spin {
-        to { transform: rotate(-10turn); }
-      }
-
-      #product-logo.spin {
-        -webkit-animation: spin 500ms cubic-bezier(1, 0, 0, 1) forwards;
-      }
-
       img {
         -webkit-margin-end: 10px;
       }
 
       iron-icon {
         -webkit-margin-end: var(--iron-icon-spacing);
       }
 
       iron-icon[icon='settings:check-circle'] {
         fill: var(--paper-blue-600);
@@ skipping 127 matching lines @@
               <settings-detailed-build-info></settings-detailed-build-info>
             </settings-subpage>
           </template>
 </if>
         </settings-animated-pages>
       </settings-section>
     </div>
   </template>
   <script src="about_page.js"></script>
 </dom-module>