Add <a is="action-link">, a web component extension of <a> for in-page actions.

chrome/browser/resources/downloads/downloads.html

Index: chrome/browser/resources/downloads/downloads.html
diff --git a/chrome/browser/resources/downloads/downloads.html b/chrome/browser/resources/downloads/downloads.html
index 837fb4b9396cca6805f987aa11bb26c6508231c2..470a189e91630cea90998e35e8cd2f93514d921e 100644
--- a/chrome/browser/resources/downloads/downloads.html
+++ b/chrome/browser/resources/downloads/downloads.html
@@ -6,6 +6,7 @@
   <link rel="stylesheet" href="chrome://resources/css/chrome_shared.css">
   <!-- This has to come after chrome_shared.css -->
   <link rel="stylesheet" href="downloads.css">
+  <script src="chrome://resources/js/action_link.js"></script>
   <script src="chrome://resources/js/load_time_data.js"></script>
   <script src="chrome://resources/js/util.js"></script>
   <script src="chrome://downloads/downloads.js"></script>
@@ -20,9 +21,8 @@
     <div class="summary" id="downloads-summary">
       <span id="downloads-summary-text"></span>
       <span id="downloads-actions">
-        <a id="open-downloads-folder" href="#"
-            i18n-content="open_downloads_folder">
-        </a>
+        <a is="action-link" id="open-downloads-folder"
+            i18n-content="open_downloads_folder"></a>
         <span id="clear-all-holder"></span>
       </span>
     </div>