Support to repeat one song in Audio Player.

ui/file_manager/audio_player/elements/control_panel.css

 /* Copyright 2014 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. */
 
 /* Controls bar. */
 .controls {
   align-items: center;
   background-color: white;
   display: flex;
   flex-direction: column;
@@ skipping 123 matching lines @@
   visibility: hidden;
 }
 
 .media-button.shuffle-mode {
   background-image: -webkit-image-set(
       url(../assets/100/player_button_shuffle.png) 1x,
       url(../assets/200/player_button_shuffle.png) 2x);
   pointer-events: auto;
 }
 
-.media-button.repeat {
+.media-button.repeat-mode {
   margin-left: 8px;
   margin-right: 0;
 }
 
-.media-button.repeat {
-  background-image: -webkit-image-set(
-      url(../assets/100/player_button_repeat.png) 1x,
-      url(../assets/200/player_button_repeat.png) 2x);
-  pointer-events: auto;
-}
-
 .media-button.play {
   margin-left: 4px;
   margin-right: 4px;
 }
 
 .media-button.play {
   background-image: -webkit-image-set(
       url(../assets/100/player_button_play.png) 1x,
       url(../assets/200/player_button_play.png) 2x);
 }
@@ skipping 43 matching lines @@
 /* Invisible div used to compute the width required for the elapsed time. */
 .time-controls > .time > .current {
   align-items: center;
   display: flex;
   flex-direction: row;
   height: 100%;
   justify-content: flex-end;
   position: absolute;
   top: -1px;
 }