DevTools: Reduce click target of ElementsTreeOutline gutter

third_party/WebKit/Source/devtools/front_end/elements/elementsTreeOutline.css

 /*
  * Copyright (c) 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.
  */
 
 .elements-disclosure {
     width: 100%;
     display: inline-block;
     line-height: normal;
@@ skipping 305 matching lines @@
 
 ol li.selected:focus .webkit-html-attribute-name {
     color: #ccc;
 }
 
 .elements-disclosure .gutter-container {
     position: absolute;
     top: 0;
     left: 0;
     cursor: pointer;
+    width: 15px;
+    height: 15px;
 }
 
 .gutter-menu-icon {
     display: none;
     transform: rotate(-90deg) scale(0.8);
     background-color: white;
     position: relative;
     left: -7px;
     top: -3px;
 }
@@ skipping 18 matching lines @@
     border-color: hsla(0,0%,0%,0.1);
 }
 
 .elements-tree-outline ol.shadow-root {
     border-color: hsla(0,0%,80%,1);
 }
 
 li.selected:not(.always-parent) + ol.children {
     border-color: hsla(216,68%,80%,1) !important;
 }