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runtime/bin/vmservice/client/lib/src/app/view_model.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of app;
 
 abstract class TableTreeRow extends Observable {
   final TableTreeRow parent;
   @observable final int depth;
   @observable final List<TableTreeRow> children = new List<TableTreeRow>();
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   }
 
   /// Fired when the tree row is expanded. Add children rows here.
   void onShow();
 
   /// Fired when the tree row is collapsed.
   void onHide();
 }
 
 class TableTree extends Observable {
-  final List<String> columnHeaders = [];
   @observable final List<TableTreeRow> rows = toObservable([]);
 
   /// Create a table tree with column [headers].
-  TableTree(List<String> headers) {
-    columnHeaders.addAll(headers);
-  }
+  TableTree();
 
   /// Initialize the table tree with the list of root children.
-  void initialize(List<TableTreeRow> children) {
+  void initialize(TableTreeRow root) {
     rows.clear();
-    rows.addAll(children);
+    root.onShow();
+    rows.addAll(root.children);
   }
 
   /// Toggle expansion of row at [rowIndex].
   void toggle(int rowIndex) {
     assert(rowIndex >= 0);
     assert(rowIndex < rows.length);
     var row = rows[rowIndex];
     if (row.toggle()) {
       _expand(row);
     } else {
       _collapse(row);
     }
   }
 
   int _index(TableTreeRow row) => rows.indexOf(row);
 
-  void _insertRow(int index, TableTreeRow row) {
-    if (index == -1) {
-      rows.add(row);
-    } else {
-      rows.insert(index, row);
-    }
-  }
-
   void _expand(TableTreeRow row) {
     int index = _index(row);
     assert(index != -1);
-    for (var i = 0; i < row.children.length; i++) {
-      _insertRow(index + i + 1, row.children[i]);
-    }
+    rows.insertAll(index + 1, row.children);
   }
 
   void _collapse(TableTreeRow row) {
     var childCount = row.children.length;
     if (childCount == 0) {
       return;
     }
     for (var i = 0; i < childCount; i++) {
       // Close all inner rows.
       if (row.children[i].expanded) {
         _collapse(row.children[i]);
       }
     }
     // Collapse this row.
     row.expanded = false;
     // Remove all children.
     int index = _index(row);
-    for (var i = 0; i < childCount; i++) {
-      rows.removeAt(index + 1);
-    }
+    rows.removeRange(index + 1, index + 1 + childCount);
   }
 }