DevTools: added "overlayContents" mode, where DevTools content is placed around and underneath inse…

Source/devtools/front_end/inspector.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 2782 matching lines @@
     display: inline-block;
     float: right;
     padding-right: 4px;
     padding-top: 4px;
     padding-left: 2px;
 }
 
 body.undocked .toolbar-close-button-item {
     display: none;
 }
+
+body.dock-to-bottom #inspector-split-view .split-view-resizer {
+    border-top: 1px solid rgb(64%, 64%, 64%);
+}
+
+body.dock-to-right #inspector-split-view .split-view-resizer {
+    border-left: 1px solid rgb(64%, 64%, 64%);
+}