DevTools: Make sure ElementsTreeOutline is correctly rendered when element's hasChildren state chan…

LayoutTests/http/tests/inspector/elements-test.js

 var initialize_ElementTest = function() {
 
 InspectorTest.findNode = function(matchFunction, callback)
 {
     callback = InspectorTest.safeWrap(callback);
     var result = null;
     var pendingRequests = 0;
     function processChildren(node)
     {
         try {
@@ skipping 486 matching lines @@
         }
     }
 
     var treeOutline = InspectorTest.firstElementsTreeOutline();
     treeOutline._updateModifiedNodes();
     print(rootNode ? treeOutline.findTreeElement(rootNode) : treeOutline, "", depth || 10000);
 };
 
 InspectorTest.expandElementsTree = function(callback)
 {
+    var expandedSomething = false;
     callback = InspectorTest.safeWrap(callback);
 
     function expand(treeItem)
     {
         var children = treeItem.children;
         for (var i = 0; children && i < children.length; ++i) {
-            children[i].expand();
-            expand(children[i]);
+            var child = children[i];
+            if (child.hasChildren && !child.expanded) {
+                child.expand();
+                expandedSomething = true;
+            }
+            expand(child);
         }
     }
 
     function onAllNodesAvailable()
     {
         InspectorTest.firstElementsTreeOutline()._updateModifiedNodes();
         expand(InspectorTest.firstElementsTreeOutline());
-        callback();
+        callback(expandedSomething);
     }
     WebInspector.inspectorView.showPanel("elements");
     InspectorTest.findNode(function() { return false; }, onAllNodesAvailable);
 };
 
 InspectorTest.dumpDOMAgentTree = function(node)
 {
     if (!WebInspector.domModel._document)
         return;
 
@@ skipping 31 matching lines @@
         var testNode = InspectorTest.expandedNodeWithId(/function\s([^(]*)/.exec(testBody)[1]);
         InspectorTest.addResult("Initial:");
         InspectorTest.dumpElementsTree(testNode);
 
         testBody(undo);
 
         function undo()
         {
             InspectorTest.addResult("Post-action:");
             InspectorTest.dumpElementsTree(testNode);
-            WebInspector.domModel.undo(redo);
+            InspectorTest.expandElementsTree(expandedCallback);
+
+            function expandedCallback(expandedSomething)
+            {
+                if (expandedSomething) {
+                    InspectorTest.addResult("== Expanded: ==");
+                    InspectorTest.dumpElementsTree(testNode);
+                }
+                WebInspector.domModel.undo(redo);
+            }
         }
 
         function redo()
         {
             InspectorTest.addResult("Post-undo (initial):");
             InspectorTest.dumpElementsTree(testNode);
-            WebInspector.domModel.redo(done);
+            InspectorTest.expandElementsTree(expandedCallback);
+
+            function expandedCallback(expandedSomething)
+            {
+                if (expandedSomething) {
+                    InspectorTest.addResult("== Expanded: ==");
+                    InspectorTest.dumpElementsTree(testNode);
+                }
+                WebInspector.domModel.redo(done);
+            }
         }
 
         function done()
         {
             InspectorTest.addResult("Post-redo (action):");
             InspectorTest.dumpElementsTree(testNode);
-            next();
+            InspectorTest.expandElementsTree(expandedCallback);
+
+            function expandedCallback(expandedSomething)
+            {
+                if (expandedSomething) {
+                    InspectorTest.addResult("== Expanded: ==");
+                    InspectorTest.dumpElementsTree(testNode);
+                }
+                next();
+            }
         }
     }
     result.toString = function()
     {
         return testBody.toString();
     }
     return result;
 }
 
 const indent = "    ";
@@ skipping 150 matching lines @@
 
 InspectorTest.dumpInspectorHighlightShape = function(node, callback)
 {
     node.boxModel(function(shapes) {
         InspectorTest.addResult(JSON.stringify(shapes.shapeOutside.shape));
         callback();
     });
 }
 
 };