Sky: update the HTMLIFrameElement's geometry during paint invalidation rather

sky/engine/core/rendering/RenderObject.h

Index: sky/engine/core/rendering/RenderObject.h
diff --git a/sky/engine/core/rendering/RenderObject.h b/sky/engine/core/rendering/RenderObject.h
index 737308507ceb014509e588226f8d35c31425e15f..8f458c365d9652d8b3c5916818db402aaa2a4224 100644
--- a/sky/engine/core/rendering/RenderObject.h
+++ b/sky/engine/core/rendering/RenderObject.h
@@ -701,6 +701,10 @@ public:
     InvalidationReason invalidatePaintIfNeeded(const RenderLayerModelObject& paintInvalidationContainer,
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer, const PaintInvalidationState&);
 
+    // Invalidates the bounds of a widget that is drawn separately from the
+    // paint step. Returns false if further invalidation is required.
+    virtual bool invalidateWidgetBounds() { return false; }
+
     // Walk the tree after layout issuing paint invalidations for renderers that have changed or moved, updating bounds that have changed, and clearing paint invalidation state.
     virtual void invalidateTreeIfNeeded(const PaintInvalidationState&);