[Devtools] Moved flatten children to children nodes instead of datagrid

third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html

Index: third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html
diff --git a/third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html b/third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html
index d31110b28a116261f5e116acc50684b9851def94..166d47a4d391195b3ec64ac3f6beb5ee655fff17 100644
--- a/third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html
+++ b/third_party/WebKit/LayoutTests/inspector/components/viewport-datagrid.html
@@ -42,6 +42,15 @@ function test()
         InspectorTest.addResult("Collapsed node " + node.data.id);
     }
 
+    function dumpFlattenChildren()
+    {
+        var nodes = dataGrid.rootNode().flatChildren();
+        InspectorTest.addResult("Checking flatChildren():");
+        for (var node of nodes)
+            InspectorTest.addResult("  " + node.data.id);
+        InspectorTest.addResult("");
+    }
+
     var columns = [{id: "id", title: "ID column", width: "250px"}];
     var dataGrid = new UI.ViewportDataGrid(columns);
     var a = new UI.ViewportDataGridNode({id: "a"});
@@ -74,8 +83,12 @@ function test()
 
     // Appending to tree.
     attach(root, a);
+    // a is collapsed.
     attach(a, aa);
+    expand(a);
+    dumpFlattenChildren();
     attach(a, ab);
+    dumpFlattenChildren();
     attach(root, b);
 
     dumpNodes();
@@ -107,11 +120,16 @@ function test()
     dumpNodes();
     attach(ab, aac);
     aac.revealAndSelect();
+    dumpFlattenChildren();
+    InspectorTest.addResult("Removed children of aa");
     aa.removeChildren();
+    dumpFlattenChildren();
     dumpNodes();
     attach(ab, aac);
     aac.revealAndSelect();
+    dumpFlattenChildren();
     detach(a, aa);
+    dumpFlattenChildren();
     dumpNodes();
     detach(a, ab);
     dumpNodes();