DevTools: Implement recursive viewport for the Heap Summary view

Source/devtools/front_end/DataGrid.js

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *        notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *        notice, this list of conditions and the following disclaimer in the
@@ skipping 1150 matching lines @@
     this.children = [];
     this.dataGrid = null;
     this.parent = null;
     /** @type {?WebInspector.DataGridNode} */
     this.previousSibling = null;
     /** @type {?WebInspector.DataGridNode} */
     this.nextSibling = null;
     this.disclosureToggleWidth = 10;
 }
 
-WebInspector.DataGridNode.NodeShallowHeight = 16;
-
 WebInspector.DataGridNode.prototype = {
     /** @type {boolean} */
     selectable: true,
 
     /** @type {boolean} */
     _isRoot: false,
 
     get element()
     {
         if (this._element)
@@ skipping 204 matching lines @@
             if (this.leftPadding)
                 cell.style.setProperty("padding-left", this.leftPadding + "px");
         }
 
         return cell;
     },
 
     /**
      * @return {number}
      */
-    nodeHeight: function()
+    nodeSelfHeight: function()
     {
-        var rowHeight = WebInspector.DataGridNode.NodeShallowHeight;
-        if (!this.revealed)
-            return 0;
-        if (!this.expanded)
-            return rowHeight;
-        var result = rowHeight;
-        for (var i = 0; i < this.children.length; i++)
-            result += this.children[i].nodeHeight();
-        return result;
+        return 16;
     },
 
     /**
      * @param {!WebInspector.DataGridNode} child
      */
     appendChild: function(child)
     {
         this.insertChild(child, this.children.length);
     },
 
@@ skipping 402 matching lines @@
 
 WebInspector.CreationDataGridNode.prototype = {
     makeNormal: function()
     {
         delete this.isCreationNode;
         delete this.makeNormal;
     },
 
     __proto__: WebInspector.DataGridNode.prototype
 }