Adds animation on a hovered directory/volume when dragging files in Files.app

chrome/browser/resources/file_manager/css/file_manager.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 html {
   height: 100%;
 }
 
 html.col-resize * {
   cursor: col-resize !important;
@@ skipping 830 matching lines @@
   border-color: hsl(214, 91%, 85%);
 }
 
 #list-container.nohover list > :not([selected]):hover,
 #list-container.nohover grid > :not([selected]):hover,
 #list-container.nohover grid > .accepts {
   background-color: transparent;
   border-color: transparent;
 }
 
+#roots-list > .accepts,
+#list-container list > .accepts,
+#list-container grid > .accepts {
+  -webkit-animation: acceptsBlink 200ms linear 1s 3;
+}
+
+@-webkit-keyframes acceptsBlink {
+  0% {
+    background-color: transparent;
+  }
+  50% {
+  }
+}
+
 .table-row-cell .filename-label,
 .thumbnail-item .filename-label,
 /* Show ellipsis in cells. The name column has different structure and overrides
    this rule. */
 .table-row-cell > div {
   display: block;
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
 }
@@ skipping 795 matching lines @@
 }
 
 list.autocomplete-suggestions[hasElementFocus] > [selected],
 list.autocomplete-suggestions[hasElementFocus] > [lead],
 list.autocomplete-suggestions:not([hasElementFocus]) > [selected],
 list.autocomplete-suggestions:not([hasElementFocus]) > [lead] {
   background-color: rgb(238, 238, 238);
   background-image: none;
   border: 1px solid white;
 }