Add icon-visibility attribute to cr.ui.Tree.

chrome/browser/resources/certificate_viewer.html

Index: chrome/browser/resources/certificate_viewer.html
diff --git a/chrome/browser/resources/certificate_viewer.html b/chrome/browser/resources/certificate_viewer.html
index 5737483fb4ac39196c1219365f8769e6cf4909dd..20dac4816c2b002613e43a96859d949f10c379cd 100644
--- a/chrome/browser/resources/certificate_viewer.html
+++ b/chrome/browser/resources/certificate_viewer.html
@@ -7,6 +7,7 @@
     <link rel="stylesheet" href="chrome://resources/css/tabs.css">
     <link rel="stylesheet" href="chrome://resources/css/tree.css">
     <script src="strings.js"></script>
+    <script src="chrome://resources/css/tree.css.js"></script>
     <script src="chrome://resources/js/cr.js"></script>
     <script src="chrome://resources/js/cr/ui.js"></script>
     <script src="chrome://resources/js/cr/ui/focus_outline_manager.js"></script>
@@ -93,11 +94,13 @@
             <!-- Details -->
             <div id="hierarchy-section" class="vertical-box">
               <span class="title" i18n-content="hierarchy"></span>
-              <div id="hierarchy" class="section-contents"></div>
+              <tree id="hierarchy" class="section-contents"
+                  icon-visibility='hidden'></tree>
             </div>
             <div id="cert-fields-section" class="vertical-box">
               <span class="title" i18n-content="certFields"></span>
-              <div id="cert-fields" class="section-contents"></div>
+              <tree id="cert-fields" class="section-contents"
+                  icon-visibility='hidden'></tree>
             </div>
             <div id="cert-field-value-section" class="vertical-box">
               <span class="title" i18n-content="certFieldVal"></span>