[Devtools] Moved DataGridNode's .parent property to proper getter/setter

third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js

Index: third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js
diff --git a/third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js b/third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js
index 5b75ec34be5fa33e591947df1fd733d64566d5fe..9884c97d820a65063b75bd3aa69bbd721352876a 100644
--- a/third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js
+++ b/third_party/WebKit/Source/devtools/front_end/data_grid/ViewportDataGrid.js
@@ -322,7 +322,7 @@ DataGrid.ViewportDataGridNode = class extends DataGrid.DataGridNode {
    */
   clearFlatNodes() {
     this._flatNodes = null;
-    var parent = /** @type {!DataGrid.ViewportDataGridNode} */ (this.parent);
+    var parent = this.parent();
     if (parent)
       parent.clearFlatNodes();
   }
@@ -365,7 +365,7 @@ DataGrid.ViewportDataGridNode = class extends DataGrid.DataGridNode {
    */
   insertChild(child, index) {
     this.clearFlatNodes();
-    if (child.parent === this) {
+    if (child.parent() === this) {
       var currentIndex = this.children.indexOf(child);
       if (currentIndex < 0)
         console.assert(false, 'Inconsistent DataGrid state');
@@ -375,7 +375,7 @@ DataGrid.ViewportDataGridNode = class extends DataGrid.DataGridNode {
         --index;
     }
     child.remove();
-    child.parent = this;
+    child.setParent(this);
     child.dataGrid = this.dataGrid;
     if (!this.children.length)
       this.setHasChildren(true);
@@ -397,7 +397,7 @@ DataGrid.ViewportDataGridNode = class extends DataGrid.DataGridNode {
       child.previousSibling.nextSibling = child.nextSibling;
     if (child.nextSibling)
       child.nextSibling.previousSibling = child.previousSibling;
-    if (child.parent !== this)
+    if (child.parent() !== this)
       throw 'removeChild: Node is not a child of this node.';
 
     child._unlink();
@@ -429,7 +429,7 @@ DataGrid.ViewportDataGridNode = class extends DataGrid.DataGridNode {
       this.wasDetached();
     }
     this.dataGrid = null;
-    this.parent = null;
+    this.setParent(null);
     this.nextSibling = null;
     this.previousSibling = null;
   }