Support to repeat one song in Audio Player.

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 879d85ef56b1255a5f1d80e409c123748e89549c..ee3c5c3b56378647bd21f64eab02e01bafa18df6 100644
--- a/ui/file_manager/audio_player/elements/audio_player.js
+++ b/ui/file_manager/audio_player/elements/audio_player.js
@@ -41,10 +41,11 @@ Polymer({
     },
 
     /**
-     * Whether the repeat button is ON.
+     * What mode the repeat button idicates.
+     * repeat-modes can be "repeat-none", "repeat-all", "repeat-one".
      */
     repeat: {
-      type: Boolean,
+      type: String,
       notify: true
     },
 
@@ -206,7 +207,7 @@ Polymer({
    * This handler is registered in the 'on-click' attribute of the element.
    */
   onControllerNextClicked: function() {
-    this.advance_(true /* forward */, true /* repeat */);
+    this.advance_(true /* forward */, "repeat-all");
   },
 
   /**
@@ -214,7 +215,7 @@ Polymer({
    * This handler is registered in the 'on-click' attribute of the element.
    */
   onControllerPreviousClicked: function() {
-    this.advance_(false /* forward */, true /* repeat */);
+    this.advance_(false /* forward */, "repeat-all");
   },
 
   /**
@@ -267,12 +268,23 @@ Polymer({
   /**
    * Goes to the previous or the next track.
    * @param {boolean} forward True if next, false if previous.
-   * @param {boolean} repeat True if repeat-mode is enabled. False otherwise.
+   * @param {string} repeatMode Repeat mode name.
    * @private
    */
-  advance_: function(forward, repeat) {
+  advance_: function(forward, repeatMode) {

[fukino, 2016/09/02 12:11:48]

I think we don't need to change this advance_ function.
Actually, in repeat-one mode, we don't advance to the next song.

Maybe we can handle the repeat-one case in scheduleAutoAdvance_.

[harukam, 2016/09/05 04:35:03]

scheduleAutoAdvance_ is called only when error happens.
So, I think we have to change not only scheduleAutoAdvance_, but also
onAudioEnded if we do not change advance_ function.
Do you think I should change these two parts, or create a new function like
repeat_or_advance_(repeatMode)?

[fukino, 2016/09/05 11:44:13]

I think this should work:
1) On onAudioEnded, we repeat the current song if repeat mode is repeat-one.
2) On onAudioError, we should stop playing, instead of schedule auto advance, if
repeat mode is repeat-one.

[harukam, 2016/09/09 04:54:50]

OK. Thanks.

+    console.assert(repeatMode == "repeat-none" || repeatMode === "repeat-all" ||
+        repeatMode == "repeat-one");
+
     this.cancelAutoAdvance_();
 
+    if(repeatMode === "repeat-one") {
+      this.playing = true;
+      this.$.audio.currentTime = 0;
+      this.$.trackList.fire('current-track-index-changed');

[harukam, 2016/09/02 11:27:27]

Question, do you think this line is necessary?
According to the definition of 'currentTrackIndexChanged' in
'audio_player/elements/track_list.js' (observer of currentTrackIndex), it
doesn't seem do anything when the index doesn't change.

[fukino, 2016/09/02 12:11:48]

According to https://codereview.chromium.org/1681843002,
the current-track-index-changed event is fired to restart playback when there is
only one song.

Please check if it works without the event firing when the mode is repeat-one
and there is only one song and the user press next/prev button.

[harukam, 2016/09/05 04:35:03]

Thanks for the link. It works without the event firing in all three modes when
there is only one song.

I don't understand why we need to fire the event though currentTrackIndexChanged
function doesn't do anything when both new value and old one are same.
In addition, currentTrackIndexChanged isn't called when we do
"this.$.trackList.fire('current-track-index-changed')".

[fukino, 2016/09/05 11:44:13]

Maybe we can drop the current-track-index-changed from advance_, but let's keep
it as it is until we can understand why it is added in the previous CL.

[harukam, 2016/09/09 04:54:50]

Acknowledged.

+      return;
+    }
+
+    var repeat = repeatMode === "repeat-all";
     var nextTrackIndex = this.$.trackList.getNextTrackIndex(forward, true);
     var isNextTrackAvailable =
         (this.$.trackList.getNextTrackIndex(forward, repeat) !== -1);
@@ -302,10 +314,10 @@ Polymer({
   /**
    * Schedules automatic advance to the next track after a timeout.
    * @param {boolean} forward True if next, false if previous.
-   * @param {boolean} repeat True if repeat-mode is enabled. False otherwise.
+   * @param {string} repeatMode Repeat mode name.
    * @private
    */
-  scheduleAutoAdvance_: function(forward, repeat) {
+  scheduleAutoAdvance_: function(forward, repeatMode) {
     this.cancelAutoAdvance_();
     var currentTrackIndex = this.currentTrackIndex;
 
@@ -325,7 +337,7 @@ Polymer({
           // We are advancing only if the next track is not known to be invalid.
           // This prevents an endless auto-advancing in the case when all tracks
           // are invalid (we will only visit each track once).
-          this.advance_(forward, repeat);
+          this.advance_(forward, repeatMode);
         }.bind(this),
         3000);