Bug 1132592 - Avoid showing PluginWidgetParent widgets before they are positioned and clipped. r=aklotz

dom/plugins/ipc/PluginWidgetParent.cpp

@@ -152,10 +152,6 @@ PluginWidgetParent::RecvCreate(nsresult* aResult)
   DebugOnly<nsresult> drv;
   drv = mWidget->EnableDragDrop(true);
   NS_ASSERTION(NS_SUCCEEDED(drv), "widget call failure");
-  drv = mWidget->Show(true);
-  NS_ASSERTION(NS_SUCCEEDED(drv), "widget call failure");
-  drv = mWidget->Enable(true);
-  NS_ASSERTION(NS_SUCCEEDED(drv), "widget call failure");
 
 #if defined(MOZ_WIDGET_GTK)
   // For setup, initially GTK code expects 'window' to hold the parent.

gfx/layers/ipc/CompositorChild.cpp

@@ -217,16 +217,18 @@ CompositorChild::RecvUpdatePluginConfigurations(const nsIntPoint& aContentOffset
                             bounds.width, bounds.height, false);
         NS_ASSERTION(NS_SUCCEEDED(rv), "widget call failure");
         nsTArray<nsIntRect> rectsOut;
+        // This call may change the value of isVisible
         CalculatePluginClip(bounds, aPlugins[pluginsIdx].clip(),
                             aContentOffset, aParentLayerVisibleRegion,
                             rectsOut, visibleBounds, isVisible);
-        if (isVisible) {
-          // content clipping region (widget origin)
-          rv = widget->SetWindowClipRegion(rectsOut, false);
-          NS_ASSERTION(NS_SUCCEEDED(rv), "widget call failure");
-        }
+        // content clipping region (widget origin)
+        rv = widget->SetWindowClipRegion(rectsOut, false);
+        NS_ASSERTION(NS_SUCCEEDED(rv), "widget call failure");
       }
 
+      rv = widget->Enable(isVisible);
+      NS_ASSERTION(NS_SUCCEEDED(rv), "widget call failure");
+
       // visible state - updated after clipping, prior to invalidating
       rv = widget->Show(isVisible);
       NS_ASSERTION(NS_SUCCEEDED(rv), "widget call failure");