Fix accessibility issues in AudioPlayer and VideoPlayer.

ui/file_manager/audio_player/elements/control_panel.js

Index: ui/file_manager/audio_player/elements/control_panel.js
diff --git a/ui/file_manager/audio_player/elements/control_panel.js b/ui/file_manager/audio_player/elements/control_panel.js
index 89562878932e291d1dcad25ac2b8ebd98db8d363..3427fe4236aa42d343e83e6b40924acb130effa6 100644
--- a/ui/file_manager/audio_player/elements/control_panel.js
+++ b/ui/file_manager/audio_player/elements/control_panel.js
@@ -16,7 +16,9 @@
       playing: {
         type: Boolean,
         value: false,
-        notify: true
+        notify: true,
+        reflectToAttribute: true,
+        observer: 'playingChanged_'
       },
 
       /**
@@ -88,6 +90,14 @@
         type: Boolean,
         value: false,
         notify: true
+      },
+
+      /**
+       * Dictionary which contains aria-labels for each controls.
+       */
+      ariaLabels: {
+        type: Object,
+        observer: 'ariaLabelsChanged_'
       }
     },
 
@@ -147,19 +157,34 @@
     },
 
     /**
-     * Computes state for play button based on 'playing' property.
-     * @return {string}
+     * Invoked when the playing property is changed.
+     * @param {boolean} playing
+     * @private
      */
-    computePlayState_: function(playing) {
-      return playing ? "playing" : "ended";
+    playingChanged_: function(playing) {
+      if (this.ariaLabels) {
+        this.$.play.setAttribute('aria-label',
+            playing ? this.ariaLabels.pause : this.ariaLabels.play);
+      }
     },
 
     /**
-     * Computes style for '.filled' element of progress bar.
-     * @return {string}
+     * Invoked when the ariaLabels property is changed.
+     * @param {Object} ariaLabels
+     * @private
      */
-    computeProgressBarStyle_: function(time, duration) {
-      return 'width: ' + (time / duration * 100) + '%;';
+    ariaLabelsChanged_: function(ariaLabels) {

[yawano, 2015/11/06 05:38:37]

small nit: assert(ariaLabels)?

[fukino, 2015/11/06 10:13:21]

Done.

+      // TODO(fukino): Use data bindings.
+      this.$.volumeSlider.setAttribute('aria-label', ariaLabels.volumeSlider);

[yawano, 2015/11/06 05:38:37]

Is it difficult to use i18nTemplate here as we do in File Manager and Gallery? -
https://code.google.com/p/chromium/codesearch#chromium/src/ui/file_manager/ga...

Using i18n-values properties seem cleaner for me.

[fukino, 2015/11/06 10:13:21]

I pass translated labels to the custom element because I don't want to make the
element dependent with VideoPlayer or cr.ui library.

+      this.$.shuffle.setAttribute('aria-label', ariaLabels.shuffle);
+      this.$.repeat.setAttribute('aria-label', ariaLabels.repeat);
+      this.$.previous.setAttribute('aria-label', ariaLabels.previous);
+      this.$.play.setAttribute('aria-label',
+          this.playing ? ariaLabels.pause : ariaLabels.play);
+      this.$.next.setAttribute('aria-label', ariaLabels.next);
+      this.$.volume.setAttribute('aria-label', ariaLabels.volume);
+      this.$.playList.setAttribute('aria-label', ariaLabels.playList);
+      this.$.timeSlider.setAttribute('aria-label', ariaLabels.seekSlider);
     }
   });
 })();  // Anonymous closure