Added checks in video player methods which may get executed after the player has been destroyed.

common/lib/xmodule/xmodule/js/src/video/03_video_player.js

@@ -70,7 +70,10 @@ function (HTML5Video, Resizer) {
     function _makeFunctionsPublic(state) {
         var debouncedF = _.debounce(
             function (params) {
-                return onSeek.call(this, params);
+                // Can't cancel a queued debounced function on destroy
+                if (state.videoPlayer) {
+                    return onSeek.call(this, params);
+                }
             }.bind(state),
             300
         );

common/lib/xmodule/xmodule/js/src/video/04_video_control.js

@@ -49,6 +49,9 @@ function () {
         });
 
         this.el.off('controls:show');
+        if (this.controlHideTimeout) {
+            clearTimeout(this.controlHideTimeout);
+        }
         delete this.videoControl;
     }
 

common/lib/xmodule/xmodule/js/src/video/09_bumper.js

@@ -86,7 +86,9 @@ define('video/09_bumper.js',[], function () {
             if (this.doNotShowAgain) {
                 _.extend(info, {bumper_do_not_show_again: true});
             }
-            this.state.videoSaveStatePlugin.saveState(true, info);
+            if (this.state.videoSaveStatePlugin) {
+                this.state.videoSaveStatePlugin.saveState(true, info);
+            }
         },
 
         destroy: function () {