tdf#71409: properly remove itself from the context it listens.

When the context itself is being disposed.  While this solves the
issue of addAccessibleEventListener() being called twice despite
removeAccessibleEventListener() being called only once, it won't
solve the problem of leaky atk focus events.

Change-Id: I984107ed2d30e6dba8067d11f400ff64d665d157

vcl/unx/gtk/a11y/atklistener.cxx

@@ -196,6 +196,15 @@ void AtkListener::handleChildRemoved(
     // for now.
     if( nIndex >= 0 )
     {
+        uno::Reference<accessibility::XAccessibleEventBroadcaster> xBroadcaster(
+            rxChild->getAccessibleContext(), uno::UNO_QUERY);
+
+        if (xBroadcaster.is())
+        {
+            uno::Reference<accessibility::XAccessibleEventListener> xListener(this);
+            xBroadcaster->removeAccessibleEventListener(xListener);
+        }
+
         updateChildList(rxParent);
 
         AtkObject * pChild = atk_object_wrapper_ref( rxChild, false );

vcl/unx/gtk/a11y/atkwrapper.cxx

@@ -846,7 +846,10 @@ atk_object_wrapper_new( const css::uno::Reference< css::accessibility::XAccessib
         {
             uno::Reference< accessibility::XAccessibleEventBroadcaster > xBroadcaster(xContext, uno::UNO_QUERY);
             if( xBroadcaster.is() )
-                xBroadcaster->addAccessibleEventListener( static_cast< accessibility::XAccessibleEventListener * > ( new AtkListener(pWrap) ) );
+            {
+                uno::Reference<accessibility::XAccessibleEventListener> xListener(new AtkListener(pWrap));
+                xBroadcaster->addAccessibleEventListener(xListener);
+            }
             else
                 OSL_ASSERT( false );
         }