[DevTools] Get rid of floats in treeoutline.

third_party/WebKit/Source/devtools/front_end/components/objectPropertiesSection.css

 /*
  * 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.
  */
 
 .object-properties-section .name {
     color: rgb(136, 19, 145);
     flex-shrink: 0;
 }
 
 .object-properties-section-separator {
     flex-shrink: 0;
 }
 
 .object-properties-section-dimmed {
     opacity: 0.6;
 }
 
 .object-properties-section {
     padding: 0 0 0px 0px;
     color: rgb(33,33,33) !important;
+    display: flex;
+    flex-direction: column;
 }
 
 .object-properties-section li {
     min-height: inherit;
     line-height: 12px;
     -webkit-user-select: text;
 }
 
 .object-properties-section li::before {
     top: -1px;
@@ skipping 10 matching lines @@
     text-overflow: clip;
 }
 
 .tree-outline ol.title-less-mode {
     padding-left: 0px;
 }
 
 .object-properties-section .synthetic-property {
     font-style: italic;
 }
+
+.object-properties-section-root-element {
+    display: flex;
+    flex-direction: row;
+}
+
+.object-properties-section-root-element::before {
+    -webkit-mask-position: -4px -97px !important;
+}
+
+.object-properties-section-root-element.expanded::before {
+    -webkit-mask-position: -20px -97px !important;
+}