[DevTools] Prepare to move Popover to shadow DOM.

third_party/WebKit/Source/devtools/front_end/elements/elementsPanel.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 361 matching lines @@
 }
 
 .animations-controls > .playback-label {
     width: 35px;
 }
 
 .styles-selector {
     cursor: text;
 }
 
-.image-preview-container {
-    background: transparent;
-    text-align: center;
-}
-
-.image-preview-container img {
-    margin: 2px auto;
-    max-width: 100px;
-    max-height: 100px;
-    background-image: url(Images/checker.png);
-    -webkit-user-select: text;
-    -webkit-user-drag: auto;
-}
-
 .metrics {
     border-bottom: 1px solid #ccc;
 }
 
 .-theme-with-dark-background .metrics {
     color: #222;
 }
 
 .-theme-with-dark-background .metrics > div:hover {
     color: #ccc;
@@ skipping 121 matching lines @@
     position: absolute;
     right: 0;
     bottom: 0;
     visibility: hidden;
     background-color: rgba(255, 255, 255, 0.9);
 }
 
 .styles-pane:not(.is-editing-style) .styles-section.matched-styles:not(.read-only):hover .sidebar-pane-section-toolbar {
     visibility: visible;
 }