Clear the buffer when switching audio streams.

* Add an optional parameter to Player.selectAudioTrack to clear
  the buffer like selectVideoTrack.

Closes #119

Change-Id: I40c4c1969115826890fe9719a988315b51e5b28c

app.js

@@ -307,13 +307,14 @@ app.checkMpdStorageStatus_ = function() {
 /**
  * Called when a new video track is selected.
  *
- * @param {boolean=} opt_immediate
+ * @param {boolean=} opt_clearBuffer If true (and by default), removes the
+ *     previous stream's content before switching to the new stream.
  */
-app.onVideoChange = function(opt_immediate) {
+app.onVideoChange = function(opt_clearBuffer) {
   var id = document.getElementById('videoTracks').value;
   document.getElementById('adaptationEnabled').checked = false;
   app.onAdaptationChange();
-  app.player_.selectVideoTrack(id, opt_immediate);
+  app.player_.selectVideoTrack(id, opt_clearBuffer);
 };
 
 
@@ -342,10 +343,13 @@ app.onAdaptationChange = function() {
 
 /**
  * Called when a new audio track is selected.
+ *
+ * @param {boolean=} opt_clearBuffer If true (and by default), removes the
+ *     previous stream's content before switching to the new stream.
  */
-app.onAudioChange = function() {
+app.onAudioChange = function(opt_clearBuffer) {
   var id = document.getElementById('audioTracks').value;
-  app.player_.selectAudioTrack(id);
+  app.player_.selectAudioTrack(id, opt_clearBuffer);
 };
 
 
@@ -365,7 +369,7 @@ app.onTextChange = function() {
  */
 app.cycleAudio = function() {
   app.cycleTracks_('cycleAudio', 'audioTracks', 3, function() {
-    app.onAudioChange();
+    app.onAudioChange(false);
   }, false);
 };
 

lib/player/player.js

@@ -491,8 +491,8 @@ shaka.player.Player.prototype.getTextTracks = function() {
  * you intend to switch to manual video track selection.
  *
  * @param {number} id The |id| field of the desired VideoTrack object.
- * @param {boolean=} opt_clearBuffer If true, removes the previous stream's
- *     content before switching to the new stream.
+ * @param {boolean=} opt_clearBuffer If true (and by default), removes the
+ *     previous stream's content before switching to the new stream.
  *
  * @return {boolean} True if the specified VideoTrack was found.
  * @export
@@ -508,13 +508,16 @@ shaka.player.Player.prototype.selectVideoTrack = function(id, opt_clearBuffer) {
  * Select an audio track by ID.
  *
  * @param {number} id The |id| field of the desired AudioTrack object.
+ * @param {boolean=} opt_clearBuffer If true (and by default), removes the
+ *     previous stream's content before switching to the new stream.
  *
  * @return {boolean} True if the specified AudioTrack was found.
  * @export
  */
-shaka.player.Player.prototype.selectAudioTrack = function(id) {
+shaka.player.Player.prototype.selectAudioTrack = function(id, opt_clearBuffer) {
   if (!this.videoSource_) return false;
-  return this.videoSource_.selectAudioTrack(id, false);
+  var clearBuffer = (opt_clearBuffer == undefined) ? true : opt_clearBuffer;
+  return this.videoSource_.selectAudioTrack(id, clearBuffer);
 };