webadmin: Use leak-free dialog re-position on Window resize

Change-Id: Ic12c323f2b4e9428e090b50a9b5030389bbbdb76
Related-To: ArcBees/GWTP#823
Signed-off-by: Vojtech Szocs <vszocs@redhat.com>

frontend/webadmin/modules/gwt-common/src/main/java/org/ovirt/engine/ui/common/presenter/AbstractPopupPresenterWidget.java

@@ -9,6 +9,7 @@
 import com.google.gwt.event.dom.client.HasClickHandlers;
 import com.google.gwt.event.dom.client.KeyCodes;
 import com.google.gwt.event.shared.EventBus;
+import com.google.gwt.event.shared.HandlerRegistration;
 import com.gwtplatform.mvp.client.PopupView;
 import com.gwtplatform.mvp.client.PresenterWidget;
 
@@ -37,6 +38,11 @@ public interface ViewDef extends PopupView {
          */
         void setPopupKeyPressHandler(PopupNativeKeyPressHandler handler);
 
+        /**
+         * @return The handler used to re-position the dialog on Window resize.
+         */
+        HandlerRegistration getRepositionOnWindowResizeHandler();
+
     }
 
     // Number of popups currently active (visible)
@@ -70,6 +76,8 @@ protected void onBind() {
                 getView().hide();
             }
         }));
+
+        registerHandler(getView().getRepositionOnWindowResizeHandler());
     }
 
     @Override

frontend/webadmin/modules/gwt-common/src/main/java/org/ovirt/engine/ui/common/view/AbstractPopupView.java

@@ -4,6 +4,8 @@
 import org.ovirt.engine.ui.common.presenter.AbstractPopupPresenterWidget;
 
 import com.google.gwt.event.shared.EventBus;
+import com.google.gwt.event.shared.HandlerRegistration;
+import com.google.gwt.user.client.Window;
 import com.google.gwt.user.client.ui.IsWidget;
 import com.google.gwt.user.client.ui.PopupPanel;
 import com.gwtplatform.mvp.client.PopupViewImpl;
@@ -31,9 +33,10 @@ protected final void initWidget(IsWidget widget) {
     }
 
     /**
-     * Return false to work around GWT-P memory leak. The resize handler implementation is broken,
-     * so turn it off
+     * TODO-GWT return false to work around GWTP memory leak
+     * The resize handler implementation is broken, so turn it off.
      * See: https://github.com/ArcBees/GWTP/issues/823
+     * Once fixed, remove {@link #getRepositionOnWindowResizeHandler} workaround.
      */
     @Override
     protected boolean repositionOnWindowResize() {
@@ -62,4 +65,13 @@ public T asWidget() {
         return (T) super.asWidget();
     }
 
+    @Override
+    public HandlerRegistration getRepositionOnWindowResizeHandler() {
+        return Window.addResizeHandler(event -> {
+            if (asPopupPanel().isShowing()) {
+                showAndReposition();
+            }
+        });
+    }
+
 }