DevTools: render category filters in a way that they don't clash.

Source/devtools/front_end/ui/splitWidget.css

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * 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 106 matching lines @@
     -webkit-mask-image: url(Images/toolbarButtonGlyphs_2x.png);
 }
 } /* media */
 
 .shadow-split-widget button.left-sidebar-show-hide-button,
 .shadow-split-widget button.top-sidebar-show-hide-button {
     top: 3px;
     left: 4px;
 }
 
-:host-context(.material).shadow-split-widget button.left-sidebar-show-hide-button,
-:host-context(.material).shadow-split-widget button.top-sidebar-show-hide-button {
+:host-context(.material) .shadow-split-widget button.left-sidebar-show-hide-button,
+:host-context(.material) .shadow-split-widget button.top-sidebar-show-hide-button {
     top: 5px;
 }
 
 .shadow-split-widget button.left-sidebar-show-hide-button:active,
 .shadow-split-widget button.top-sidebar-show-hide-button:active {
     top: 4px;
     left: 3px;
 }
 
 .shadow-split-widget button.right-sidebar-show-hide-button {
     top: 3px;
     right:2px;
 }
 
-:host-context(.material).shadow-split-widget button.right-sidebar-show-hide-button {
+:host-context(.material) .shadow-split-widget button.right-sidebar-show-hide-button {
     top: 5px;
     right: 5px;
 }
 
 .shadow-split-widget button.right-sidebar-show-hide-button:active {
     top: 4px;
     right: 1px;
 }
 
 .shadow-split-widget button.bottom-sidebar-show-hide-button {
     bottom: 1px;
     right: 1px;
 }
 
-:host-context(.material).shadow-split-widget button.bottom-sidebar-show-hide-button {
+:host-context(.material) .shadow-split-widget button.bottom-sidebar-show-hide-button {
     bottom: 3px;
     right: 3px;
 }
 
 .shadow-split-widget button.bottom-sidebar-show-hide-button:active {
     bottom: 0;
     right: 0;
 }
 
 .shadow-split-widget button.left-sidebar-show-hide-button.toggled-show {
@@ skipping 24 matching lines @@
 
 .shadow-split-widget button.bottom-sidebar-show-hide-button.toggled-show {
     -webkit-mask-position: -296px -76px; /* <| */
     transform: rotate(90deg);
 }
 
 .shadow-split-widget button.bottom-sidebar-show-hide-button.toggled-hide {
     -webkit-mask-position: -264px -76px; /* >| */
     transform: rotate(90deg);
 }