AudioPlayer: Start playing a track when play icon on the track list is clicked.

ui/file_manager/audio_player/elements/audio_player.js

Index: ui/file_manager/audio_player/elements/audio_player.js
diff --git a/ui/file_manager/audio_player/elements/audio_player.js b/ui/file_manager/audio_player/elements/audio_player.js
index 3d5fc01410f187a30115251c438f044aed636760..b459f8e8c41d3ed832da2f569a7391a2bd6b7727 100644
--- a/ui/file_manager/audio_player/elements/audio_player.js
+++ b/ui/file_manager/audio_player/elements/audio_player.js
@@ -275,6 +275,13 @@ Polymer({
   },
 
   /**
+   * Invoked when receivig a request to start playing the current music.
+   */
+  onPlayCurrentTrack: function() {
+    this.$.audio.play();
+  },
+
+  /**
    * Invoked when receiving a request to replay the current music from the track
    * list element.
    */