Introduce a button to toggle hiding/showing of the details in the events tab.

chrome/browser/resources/sync_internals/events.js

Index: chrome/browser/resources/sync_internals/events.js
diff --git a/chrome/browser/resources/sync_internals/events.js b/chrome/browser/resources/sync_internals/events.js
index 0cda0860a6c521b6e6e31fc79c06bab09677f89f..8ff80bd66eae39b536fc241c2fb906c33c012d74 100644
--- a/chrome/browser/resources/sync_internals/events.js
+++ b/chrome/browser/resources/sync_internals/events.js
@@ -3,7 +3,17 @@
 // found in the LICENSE file.
 
 (function() {
-function makeLogEntryNode(entry) {
+'use strict';
+var toggleDisplayDetails = function() {
+  var detailsNode = this.parentNode.getElementsByClassName('details')[0];
+  if (detailsNode.classList.contains('hidden')) {
+    detailsNode.classList.remove('hidden');
+  } else {
+    detailsNode.classList.add('hidden');
+  }
+}

[kjiwa, 2013/11/05 00:21:56]

As a minor note this function can be generalized if you ever want to toggle
other classes. e.g.

var toggleClass = function(e, c) {
  if (e.classList.contains(c)) {
    e.classList.remove(c);
  } else {
    e.classList.add(c);
  }
}

// ...

detailsToggleButton.addEventListener('click', function() { toggleClass(details,
'hidden'); }, false);

+
+var makeLogEntryNode = function(entry) {
   var timeNode = document.createElement('td');
   timeNode.textContent = entry.date;
 
@@ -15,7 +25,13 @@ function makeLogEntryNode(entry) {
 
   var details = document.createElement('pre');
   details.textContent = JSON.stringify(entry.details, null, 2);
+  details.className = 'details';
+  details.classList.add('hidden');

[kjiwa, 2013/11/05 00:21:56]

For consistency you may want to use:

  details.classList.add("details");
  details.classList.add("hidden");

+  var detailsToggleButton = document.createElement('button');
+  detailsToggleButton.addEventListener('click', toggleDisplayDetails, false);
+  detailsToggleButton.textContent = 'Show/Hide Details';
   var detailsNode = document.createElement('td');
+  detailsNode.appendChild(detailsToggleButton);
   detailsNode.appendChild(details);
 
   var node = document.createElement('tr');