Don't always clear buffer in configure

It appears that we were clearing the buffers when we re-configured the
ABR manager. This was not necessary, so instead we do not clear the
buffers so that any buffered data can be used.

Change-Id: I3b57278fc47eed4d36e91e0e59211f374dfdfc06
Issue: #1009

lib/player.js

@@ -923,15 +923,19 @@ shaka.Player.prototype.configure = function(config) {
   shaka.util.ConfigUtils.mergeConfigObjects(
       this.config_, config, this.defaultConfig_(), this.configOverrides_(), '');
 
-  this.applyConfig_();
+  // We only need to clear buffers is the user is changing a setting that we
+  // need to see reflected immediately.
+  var clearBuffer = 'restrictions' in config;
+  this.applyConfig_(clearBuffer);
 };
 
 
 /**
  * Apply config changes.
+ * @param {boolean} clearBuffer
  * @private
  */
-shaka.Player.prototype.applyConfig_ = function() {
+shaka.Player.prototype.applyConfig_ = function(clearBuffer) {
   if (this.parser_) {
     this.parser_.configure(this.config_.manifest);
   }
@@ -952,7 +956,7 @@ shaka.Player.prototype.applyConfig_ = function() {
     // May need to choose new streams.
     shaka.log.debug('Choosing new streams after changing configuration');
     var period = this.streamingEngine_.getCurrentPeriod();
-    this.chooseStreamsAndSwitch_(period);
+    this.chooseStreamsAndSwitch_(period, clearBuffer);
   }
 
   if (this.abrManager_) {
@@ -1017,7 +1021,9 @@ shaka.Player.prototype.resetConfiguration = function() {
   // dictionaries like drm.servers.
   this.config_ = this.defaultConfig_();
 
-  this.applyConfig_();
+  // Rather than checking if it makes sense to clear the buffers based on which
+  // values are getting reset, just clear them.
+  this.applyConfig_(true);
 };
 
 
@@ -1417,7 +1423,7 @@ shaka.Player.prototype.selectAudioLanguage = function(language, opt_role) {
   var period = this.streamingEngine_.getCurrentPeriod();
   this.currentAudioLanguage_ = language;
   this.currentVariantRole_ = opt_role || '';
-  this.chooseStreamsAndSwitch_(period);
+  this.chooseStreamsAndSwitch_(period, true);
 };
 
 
@@ -1434,7 +1440,7 @@ shaka.Player.prototype.selectTextLanguage = function(language, opt_role) {
   var period = this.streamingEngine_.getCurrentPeriod();
   this.currentTextLanguage_ = language;
   this.currentTextRole_ = opt_role || '';
-  this.chooseStreamsAndSwitch_(period);
+  this.chooseStreamsAndSwitch_(period, true);
 };
 
 
@@ -1662,7 +1668,7 @@ shaka.Player.prototype.addTextTrack = function(
         this.loadingTextStreamIds_.indexOf(stream.id), 1);
 
     shaka.log.debug('Choosing new streams after adding a text stream');
-    this.chooseStreamsAndSwitch_(period);
+    this.chooseStreamsAndSwitch_(period, true);
     this.onTracksChanged_();
 
     return {
@@ -2398,9 +2404,10 @@ shaka.Player.prototype.chooseVariant_ = function(variants) {
  * explicit language change.
  *
  * @param {!shakaExtern.Period} period
+ * @param {!boolean} clearBuffer
  * @private
  */
-shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period) {
+shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period, clearBuffer) {
   goog.asserts.assert(this.config_, 'Must not be destroyed');
 
   var variants = shaka.util.StreamUtils.filterVariantsByLanguageAndRole(
@@ -2414,7 +2421,7 @@ shaka.Player.prototype.chooseStreamsAndSwitch_ = function(period) {
   var chosenVariant = this.chooseVariant_(variants);
   if (chosenVariant) {
     this.addVariantToSwitchHistory_(chosenVariant, /* fromAdaptation */ true);
-    this.switchVariant_(chosenVariant, /* opt_clearBuffer */ true);
+    this.switchVariant_(chosenVariant, clearBuffer);
   }
 
   var chosenText = textStreams[0];
@@ -2809,7 +2816,7 @@ shaka.Player.prototype.onKeyStatus_ = function(keyStatusMap) {
       period.variants);
   if (activeVariant && !activeVariant.allowedByKeySystem) {
     shaka.log.debug('Choosing new streams after key status changed');
-    this.chooseStreamsAndSwitch_(period);
+    this.chooseStreamsAndSwitch_(period, true);
   }
 
   if (tracksChanged)