DevTools: Make children field of the CpuProfileNode optional in the protocol.

third_party/WebKit/Source/devtools/front_end/sdk/CPUProfileDataModel.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.ProfileNode}
  * @param {!ProfilerAgent.CPUProfileNode} node
  * @param {number} sampleTime
  */
@@ skipping 94 matching lines @@
         var keepNatives = !!WebInspector.moduleSetting("showNativeFunctionsInJSProfile").get();
         var root = nodes[0];
         /** @type {!Map<number, number>} */
         var idMap = new Map([[root.id, root.id]]);
         var resultRoot = new WebInspector.CPUProfileNode(root, sampleTime);
         var parentNodeStack = root.children.map(() => resultRoot);
         var sourceNodeStack = root.children.map(id => nodeByIdMap.get(id));
         while (sourceNodeStack.length) {
             var parentNode = parentNodeStack.pop();
             var sourceNode = sourceNodeStack.pop();
+            if (!sourceNode.children)
+                sourceNode.children = [];
             var targetNode = new WebInspector.CPUProfileNode(sourceNode, sampleTime);
             if (keepNatives || !isNativeNode(sourceNode)) {
                 parentNode.children.push(targetNode);
                 parentNode = targetNode;
             } else {
                 parentNode.self += targetNode.self;
             }
             idMap.set(sourceNode.id, parentNode.id);
             parentNodeStack.push.apply(parentNodeStack, sourceNode.children.map(() => parentNode));
             sourceNodeStack.push.apply(sourceNodeStack, sourceNode.children.map(id => nodeByIdMap.get(id)));
@@ skipping 197 matching lines @@
      * @param {number} index
      * @return {?WebInspector.CPUProfileNode}
      */
     nodeByIndex: function(index)
     {
         return this._idToNode.get(this.samples[index]) || null;
     },
 
     __proto__: WebInspector.ProfileTreeModel.prototype
 }