[WebProfiler] Fix race condition in fast Ajax requests

Patch startAjaxRequest and finishAjaxRequest functions to absolute noop
in case the debug toolbar itself is not loaded yet, and spool historic
requests after the toolbar is loaded.

Fixes symfony#22297

Author: curry684

src/Symfony/Bundle/WebProfilerBundle/Resources/views/Profiler/base_js.html.twig

@@ -117,16 +117,16 @@
         };
 
         var startAjaxRequest = function(index) {
-            var request = requestStack[index];
-            pendingRequests++;
-            var row = document.createElement('tr');
-            request.DOMNode = row;
-
             var tbody = document.querySelector('.sf-toolbar-ajax-request-list');
             if (!tbody) {
                 return;
             }
 
+            var request = requestStack[index];
+            pendingRequests++;
+            var row = document.createElement('tr');
+            request.DOMNode = row;
+
             var methodCell = document.createElement('td');
             methodCell.textContent = request.method;
             row.appendChild(methodCell);
@@ -171,6 +171,9 @@
 
         var finishAjaxRequest = function(index) {
             var request = requestStack[index];
+            if (!request.DOMNode) {
+                return;
+            }
             pendingRequests--;
             var row = request.DOMNode;
             /* Unpack the children from the row */
@@ -356,6 +359,12 @@
                             el.innerHTML = xhr.responseText;
                             el.setAttribute('data-sfurl', url);
                             removeClass(el, 'loading');
+                            for (var i = 0; i < requestStack.length; i++) {
+                                startAjaxRequest(i);
+                                if (requestStack[i].duration) {
+                                    finishAjaxRequest(i);
+                                }
+                            }
                             (onSuccess || noop)(xhr, el);
                         },
                         function(xhr) { (onError || noop)(xhr, el); },