DevTools: make toolbar button click targets square

Source/devtools/front_end/sidebarPane.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 16 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 .sidebar-pane {
     position: relative;
     flex-direction: column;
     display: flex;
     flex: none;
 }
 
+.sidebar-pane-hidden {
+    display: none;
+}
+
 .sidebar-pane .info {
     text-align: center;
     font-style: italic;
     padding: 6px;
     color: #888;
 }
 
 .sidebar-pane .section .properties-tree {
     padding-left: 16px;
 }
@@ skipping 14 matching lines @@
     overflow: hidden;
     position: relative;
 }
 
 .sidebar-pane-title.expanded,
 .sidebar-pane-title:last-child {
     border-bottom: 1px solid #ddd;
 }
 
 .sidebar-pane-title:first-child {
-    border-top: none;
+    /* border-top: none; */

[dgozman, 2015/06/11 16:14:12]

commented css

[pfeldman, 2015/06/11 16:38:06]

Done.

 }
 
 .sidebar-pane-title::before {
     background-image: url(Images/toolbarButtonGlyphs.png);
     background-size: 352px 144px;
     opacity: 0.5;
     float: left;
     width: 11px;
     height: 11px;
     margin-right: 2px;
@@ skipping 57 matching lines @@
     visibility: hidden;
 }
 
 .styles-section.matched-styles:not(.read-only):hover .sidebar-pane-button-new-rule {
     visibility: visible;
 }
 
 .sidebar-pane-button-new-rule:hover {
     background-position: -23px 0;
 }