DevTools: do not make main panel unconditionally focused by default.

third_party/WebKit/Source/devtools/front_end/emulation/AdvancedApp.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.
 /**
  * @implements {Common.App}
  * @unrestricted
  */
 Emulation.AdvancedApp = class {
   constructor() {
     Components.dockController.addEventListener(
@@ skipping 11 matching lines @@
 
   /**
    * @override
    * @param {!Document} document
    */
   presentUI(document) {
     var rootView = new UI.RootView();
 
     this._rootSplitWidget = new UI.SplitWidget(false, true, 'InspectorView.splitViewState', 555, 300, true);
     this._rootSplitWidget.show(rootView.element);
-
     this._rootSplitWidget.setSidebarWidget(UI.inspectorView);
+    this._rootSplitWidget.setDefaultFocusedChild(UI.inspectorView);
     UI.inspectorView.setOwnerSplit(this._rootSplitWidget);
 
     this._inspectedPagePlaceholder = new Emulation.InspectedPagePlaceholder();
     this._inspectedPagePlaceholder.addEventListener(
         Emulation.InspectedPagePlaceholder.Events.Update, this._onSetInspectedPageBounds.bind(this), this);
     this._deviceModeView = new Emulation.DeviceModeWrapper(this._inspectedPagePlaceholder);
 
     Components.dockController.addEventListener(
         Components.DockController.Events.BeforeDockSideChanged, this._onBeforeDockSideChange, this);
     Components.dockController.addEventListener(
         Components.DockController.Events.DockSideChanged, this._onDockSideChange, this);
     Components.dockController.addEventListener(
         Components.DockController.Events.AfterDockSideChanged, this._onAfterDockSideChange, this);
     this._onDockSideChange();
 
     console.timeStamp('AdvancedApp.attachToBody');
     rootView.attachToDocument(document);
+    rootView.focus();
     this._inspectedPagePlaceholder.update();
   }
 
   /**
    * @param {!Common.Event} event
    */
   _openToolboxWindow(event) {
     if (/** @type {string} */ (event.data.to) !== Components.DockController.State.Undocked)
       return;
 
@@ skipping 124 matching lines @@
  */
 Emulation.AdvancedAppProvider = class {
   /**
    * @override
    * @return {!Common.App}
    */
   createApp() {
     return Emulation.AdvancedApp._instance();
   }
 };