sink: Automatically draw black when going to NULL state

Remove all workarounds including ignore_textures prop and draw black functions and handle that automatically in sink when going into NULL state.

src/controls.js

@@ -247,9 +247,6 @@ class ClapperControls extends Gtk.Box
         }
 
         if(checkButton.activeId < 0) {
-            if(checkButton.type === 'video')
-                clapperWidget.player.draw_black(true);
-
             return clapperWidget.player[
                 `set_${checkButton.type}_track_enabled`
             ](false);
@@ -259,9 +256,6 @@ class ClapperControls extends Gtk.Box
 
         clapperWidget.player[setTrack](checkButton.activeId);
         clapperWidget.player[`${setTrack}_enabled`](true);
-
-        if(checkButton.type === 'video')
-            clapperWidget.player.draw_black(false);
     }
 
     _handleVisualizationChange(checkButton)

src/player.js

@@ -133,14 +133,6 @@ class ClapperPlayer extends GstClapper.Clapper
         debug(`changed rank: ${oldRank} -> ${rank} for ${name}`);
     }
 
-    draw_black(isEnabled)
-    {
-        this.widget.ignore_textures = isEnabled;
-
-        if(this.state !== GstClapper.ClapperState.PLAYING)
-            this.widget.queue_render();
-    }
-
     set_uri(uri)
     {
         this.customVideoTitle = null;