Settings Router Refactor: Remove route.page legacy property.

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 47 matching lines @@
       }
 
       .info-section {
         margin-bottom: 12px;
       }
 
       #regulatoryInfo img {
         width: 330px;
       }
     </style>
-    <div data-page="about">
+    <div>
       <settings-section page-title="$i18n{aboutPageTitle}"
           current-route="[[currentRoute]]" section="about">
         <settings-animated-pages id="pages" current-route="{{currentRoute}}"
             section="about">
           <neon-animatable id="main">
             <div class="settings-box">
               <img id="product-logo"
                   srcset="chrome://theme/current-channel-logo@1x 1x,
                           chrome://theme/current-channel-logo@2x 2x" alt="">
               <span class="product-title">$i18n{aboutProductTitle}</span>
@@ skipping 97 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>