Fix for broken CertificateViewerUITest.testDetails.

chrome/browser/resources/certificate_viewer.js

Index: chrome/browser/resources/certificate_viewer.js
diff --git a/chrome/browser/resources/certificate_viewer.js b/chrome/browser/resources/certificate_viewer.js
index 417f5604149127090ba1f345c62099a21237d685..d8223b1100805d84acfd26e0f120f0a4f5c38398 100644
--- a/chrome/browser/resources/certificate_viewer.js
+++ b/chrome/browser/resources/certificate_viewer.js
@@ -17,17 +17,31 @@ cr.define('cert_viewer', function() {
     var args = JSON.parse(chrome.dialogArguments);
     getCertificateInfo(args);
 
+    /**
+     * Initialize the second tab's contents.
+     * This is a 'oneShot' function, meaning it will only be invoked once,
+     * no matter how many times it is called.  This is done for unit-testing
+     * purposes in case a test needs to initialize the tab before the timer
+     * fires.
+     */
+    var initializeDetailTab = oneShot(function() {
+      initializeTree($('hierarchy'), showCertificateFields);
+      initializeTree($('cert-fields'), showCertificateFieldValue);
+      createCertificateHierarchy(args.hierarchy);
+    });
+
     // The second tab's contents aren't visible on startup, so we can
     // shorten startup by not populating those controls until after we
     // have had a chance to draw the visible controls the first time.
     // The value of 200ms is quick enough that the user couldn't open the
     // tab in that time but long enough to allow the first tab to draw on
     // even the slowest machine.
-    setTimeout(function() {
-      initializeTree($('hierarchy'), showCertificateFields);
-      initializeTree($('cert-fields'), showCertificateFieldValue);
-      createCertificateHierarchy(args.hierarchy);
-    }, 200);
+    setTimeout(initializeDetailTab, 200);
+
+    $('tabbox').addEventListener('selectedChange', function f(e) {
+      $('tabbox').removeEventListener('selectedChange', f);
+      initializeDetailTab();
+    }, true);
 
     stripGtkAccessorKeys();
 
@@ -41,6 +55,18 @@ cr.define('cert_viewer', function() {
   }
 
   /**
+   * Decorate a function so that it can only be invoked once.
+   */
+  function oneShot(fn) {
+    var fired = false;
+    return function() {
+       if (fired) return;
+       fn();
+       fired = true;
+    };
+  }
+
+  /**
    * Initialize a cr.ui.Tree object from a given element using the specified
    * change handler.
    * @param {HTMLElement} tree The HTMLElement to style as a tree.