[Devtools] Fix left margin for selection element

third_party/WebKit/Source/devtools/front_end/accessibility/AXTreePane.js

 // Copyright 2016 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
  */
 Accessibility.AXTreePane = class extends Accessibility.AccessibilitySubPane {
   /**
    * @param {!Accessibility.AccessibilitySidebarView} axSidebarView
    */
   constructor(axSidebarView) {
     super(Common.UIString('Accessibility Tree'));
 
     this._axSidebarView = axSidebarView;
     this._treeOutline = this.createTreeOutline();
+    this._treeOutline.setPaddingSize(12);
 
     this.element.classList.add('accessibility-computed');
 
     this._expandedNodes = new Set();
   }
 
   /**
    * @param {?Accessibility.AccessibilityNode} axNode
    * @override
    */
@@ skipping 402 matching lines @@
         continue;
       }
       siblingTreeElement = new Accessibility.AXNodeTreeElement(sibling, this._treePane);
       if (foundInspectedNode)
         this.appendChild(siblingTreeElement);
       else
         this.insertChild(siblingTreeElement, nextIndex++);
     }
   }
 };