DevTools: Add scroll bar to the JSON view.

third_party/WebKit/Source/devtools/front_end/network/networkPanel.css

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Anthony Ricaud <rik@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 204 matching lines @@
 .network-overview .resources-dividers-label-bar .resources-divider {
     background-color: transparent;
 }
 
 .network-overview .resources-dividers {
     z-index: 250;
 }
 
 .json-view {
     padding: 2px 6px;
+    overflow: auto;
 }
 
 .request-view.html iframe {
     width: 100%;
     height: 100%;
     position: absolute;
 }
 
 .network-film-strip {
     border-bottom: solid 1px #cdcdcd;
     flex: none !important;
 }
 
 .network-blocked-urls {
     border-top: 1px solid #dadada;
     flex: 104px 0 0;
 }