Disable video when the media element is AUDIO (#2371)

Closes #2246

Backported to v2.5.x

Change-Id: Ia32d46409f7b90ec5b7494c1682c79a5c969bc55

lib/player.js

@@ -1442,7 +1442,13 @@ shaka.Player.prototype.onInitializeParser_ = async function(has, wants) {
         has.mimeType);
   }
 
-  this.parser_.configure(this.config_.manifest);
+  const manifestConfig =
+      shaka.util.ObjectUtils.cloneObject(this.config_.manifest);
+  // Don't read video segments if the player is attached to an audio element
+  if (wants.mediaElement && wants.mediaElement.nodeName === 'AUDIO') {
+    manifestConfig.disableVideo = true;
+  }
+  this.parser_.configure(manifestConfig);
 };
 
 
@@ -2394,7 +2400,13 @@ shaka.Player.prototype.configure = function(config, value) {
  */
 shaka.Player.prototype.applyConfig_ = function() {
   if (this.parser_) {
-    this.parser_.configure(this.config_.manifest);
+    const manifestConfig =
+        shaka.util.ObjectUtils.cloneObject(this.config_.manifest);
+    // Don't read video segments if the player is attached to an audio element
+    if (this.video_ && this.video_.nodeName === 'AUDIO') {
+      manifestConfig.disableVideo = true;
+    }
+    this.parser_.configure(manifestConfig);
   }
   if (this.drmEngine_) {
     this.drmEngine_.configure(this.config_.drm);