[DevTools] Fix UI extreme cases: very small window and very large zoom.

Source/devtools/front_end/main/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.
 
 /**
  * @constructor
  * @extends {WebInspector.App}
  */
 WebInspector.AdvancedApp = function()
 {
     WebInspector.App.call(this);
     WebInspector.dockController.addEventListener(WebInspector.DockController.Events.BeforeDockSideChanged, this._openToolboxWindow, this);
 };
 
 WebInspector.AdvancedApp.prototype = {
     createRootView: function()
     {
         var rootView = new WebInspector.RootView();
 
-        this._rootSplitView = new WebInspector.SplitView(false, true, WebInspector.dockController.canDock() ? "InspectorView.splitViewState" : "InspectorView.dummySplitViewState", 300, 300);
+        this._rootSplitView = new WebInspector.SplitView(false, true, WebInspector.dockController.canDock() ? "InspectorView.splitViewState" : "InspectorView.dummySplitViewState", 300, 300, true);
         this._rootSplitView.show(rootView.element);
 
         WebInspector.inspectorView.show(this._rootSplitView.sidebarElement());
 
         this._inspectedPagePlaceholder = new WebInspector.InspectedPagePlaceholder();
         this._inspectedPagePlaceholder.addEventListener(WebInspector.InspectedPagePlaceholder.Events.Update, this._onSetInspectedPageBounds.bind(this, false), this);
         this._responsiveDesignView = new WebInspector.ResponsiveDesignView(this._inspectedPagePlaceholder);
         this._responsiveDesignView.show(this._rootSplitView.mainElement());
 
         WebInspector.dockController.addEventListener(WebInspector.DockController.Events.BeforeDockSideChanged, this._onBeforeDockSideChange, this);
@@ skipping 145 matching lines @@
 
     var advancedApp = /** @type {!WebInspector.AdvancedApp} */ (window.opener.WebInspector.app);
     var rootView = new WebInspector.RootView();
     this._inspectedPagePlaceholder = new WebInspector.InspectedPagePlaceholder();
     this._inspectedPagePlaceholder.addEventListener(WebInspector.InspectedPagePlaceholder.Events.Update, advancedApp._onSetInspectedPageBounds.bind(advancedApp, true));
     this._responsiveDesignView = new WebInspector.ResponsiveDesignView(this._inspectedPagePlaceholder);
     this._responsiveDesignView.show(rootView.element);
     rootView.attachToBody();
     advancedApp._toolboxLoaded(this);
 }