DevTools: introduce object previews experiment

third_party/WebKit/Source/devtools/front_end/components/objectValue.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-value-scientific-notation-exponent {
     flex-shrink: 0;
 }
 
@@ skipping 80 matching lines @@
     display: inline-flex;
     flex-direction: column;
 }
 
 .-theme-with-dark-background .object-value-number,
 :host-context(.-theme-with-dark-background) .object-value-number,
 .-theme-with-dark-background .object-value-boolean,
 :host-context(.-theme-with-dark-background) .object-value-boolean {
     color: hsl(252, 100%, 75%);
 }
+
+.object-preview .object-description {
+    color: gray;
+}