Qt4: keep the vout thread, not its ID

The window is always created with a pre-existing video output,
and destroyed before the video outout.

Besides, using object IDs is not safe.

modules/gui/qt4/components/interface_widgets.cpp

@@ -66,7 +66,7 @@
 VideoWidget::VideoWidget( intf_thread_t *_p_i ) : QFrame( NULL ), p_intf( _p_i )
 {
     /* Init */
-    i_vout = 0;
+    p_vout = NULL;
     videoSize.rwidth() = -1;
     videoSize.rheight() = -1;
 
@@ -109,15 +109,10 @@ void VideoWidget::paintEvent(QPaintEvent *ev)
 /* Kill the vout at Destruction */
 VideoWidget::~VideoWidget()
 {
-    vout_thread_t *p_vout = i_vout ?
-        (vout_thread_t *)vlc_object_get( p_intf->p_libvlc, i_vout ) : NULL;
-
-    if( p_vout )
-    {
+    if( !p_vout )
+        return;
     if( vout_Control( p_vout, VOUT_CLOSE ) != VLC_SUCCESS )
         vout_Control( p_vout, VOUT_REPARENT );
-        vlc_object_release( p_vout );
-    }
 }
 
 /**
@@ -128,12 +123,12 @@ void *VideoWidget::request( vout_thread_t *p_nvout, int *pi_x, int *pi_y,
 {
     msg_Dbg( p_intf, "Video was requested %i, %i", *pi_x, *pi_y );
     emit askVideoWidgetToShow( *pi_width, *pi_height );
-    if( i_vout )
+    if( p_vout )
     {
         msg_Dbg( p_intf, "embedded video already in use" );
         return NULL;
     }
-    i_vout = p_nvout->i_object_id;
+    p_vout = p_nvout;
 #ifndef NDEBUG
     msg_Dbg( p_intf, "embedded video ready (handle %p)", winId() );
 #endif
@@ -155,7 +150,7 @@ void VideoWidget::SetSizing( unsigned int w, unsigned int h )
 void VideoWidget::release( void *p_win )
 {
     msg_Dbg( p_intf, "Video is not needed anymore" );
-    i_vout = 0;
+    p_vout = NULL;
     videoSize.rwidth() = 0;
     videoSize.rheight() = 0;
     updateGeometry();

modules/gui/qt4/components/interface_widgets.hpp

@@ -65,7 +65,7 @@ public:
     virtual QSize sizeHint() const;
 private:
     intf_thread_t *p_intf;
-    int i_vout;
+    vout_thread_t *p_vout;
 
     QSize videoSize;