[DevTools] Dock to left mode.

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 570 matching lines @@
 }
 
 button.status-bar-item.dock-status-bar-item.toggled-bottom .glyph {
     -webkit-mask-position: -32px -24px;
 }
 
 button.status-bar-item.dock-status-bar-item.toggled-right .glyph {
     -webkit-mask-position: -256px -48px;
 }
 
+button.status-bar-item.dock-status-bar-item.toggled-left .glyph {
+    -webkit-mask-position: -32px -120px;
+}
+
 body.undocked .alternate-status-bar-buttons-bar {
     margin-left: 1px;
 }
 
 .alternate-status-bar-buttons-bar {
     position: absolute;
     width: 31px;
     bottom: -3px;
     background: white;
 }
@@ skipping 2248 matching lines @@
     padding-left: 2px;
 }
 
 body.undocked .toolbar-close-button-item {
     display: none;
 }
 
 body.dock-to-bottom #inspector-split-view > .split-view-resizer {
     display: none;
 }
+
+#inspector-split-view > .split-view-sidebar {
+    position: relative;
+}