DevTools: do not update timeline tree view details if not visible.

third_party/WebKit/Source/devtools/front_end/timeline/TimelineTreeView.js

 // Copyright 2015 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.
 
 /**
  * @unrestricted
  * @implements {UI.Searchable}
  */
 Timeline.TimelineTreeView = class extends UI.VBox {
   constructor() {
@@ skipping 66 matching lines @@
     this._dataGrid.setRowContextMenuCallback(this._onContextMenu.bind(this));
     this._dataGrid.asWidget().show(mainView.element);
     this._dataGrid.addEventListener(DataGrid.DataGrid.Events.SelectedNode, this._updateDetailsForSelection, this);
 
     this._detailsView = new UI.VBox();
     this._detailsView.element.classList.add('timeline-details-view', 'timeline-details-view-body');
     this._splitWidget.setMainWidget(mainView);
     this._splitWidget.setSidebarWidget(this._detailsView);
     this._splitWidget.hideSidebar();
     this._splitWidget.show(this.element);
+    this._splitWidget.addEventListener(UI.SplitWidget.Events.ShowModeChanged, this._updateDetailsForSelection, this);
 
     /** @type {?TimelineModel.TimelineProfileTree.Node|undefined} */
     this._lastSelectedNode;
   }
 
   /**
    * @protected
    * @return {?TimelineModel.TimelineProfileTree.Node|undefined}
    */
   lastSelectedNode() {
@@ skipping 254 matching lines @@
     }
   }
 
   _updateDetailsForSelection() {
     var selectedNode = this._dataGrid.selectedNode ?
         /** @type {!Timeline.TimelineTreeView.TreeGridNode} */ (this._dataGrid.selectedNode)._profileNode :
         null;
     if (selectedNode === this._lastSelectedNode)
       return;
     this._lastSelectedNode = selectedNode;
+    if (this._splitWidget.showMode() === UI.SplitWidget.ShowMode.OnlyMain)
+      return;
     this._detailsView.detachChildWidgets();
     this._detailsView.element.removeChildren();
     if (!selectedNode || !this._showDetailsForNode(selectedNode)) {
       var banner = this._detailsView.element.createChild('div', 'full-widget-dimmed-banner');
       banner.createTextChild(Common.UIString('Select item for details.'));
     }
   }
 
   /**
    * @param {!TimelineModel.TimelineProfileTree.Node} node
@@ skipping 616 matching lines @@
 
   _onSelectionChanged() {
     this.dispatchEventToListeners(Timeline.TimelineStackView.Events.SelectionChanged);
   }
 };
 
 /** @enum {symbol} */
 Timeline.TimelineStackView.Events = {
   SelectionChanged: Symbol('SelectionChanged')
 };