Fix pixel snapping issues when layers become composited

Source/core/rendering/RenderLayerCompositor.cpp

Index: Source/core/rendering/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/RenderLayerCompositor.cpp b/Source/core/rendering/RenderLayerCompositor.cpp
index f2b31f68b7129e01433a48b355d31b0568dc9a4b..5472663f87251db867fabc05347b3f0d457e2c56 100644
--- a/Source/core/rendering/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/RenderLayerCompositor.cpp
@@ -640,10 +640,10 @@ void RenderLayerCompositor::repaintInCompositedAncestor(RenderLayer* layer, cons
 
 // The bounds of the GraphicsLayer created for a compositing layer is the union of the bounds of all the descendant
 // RenderLayers that are rendered by the composited RenderLayer.
-IntRect RenderLayerCompositor::calculateCompositedBounds(const RenderLayer* layer, const RenderLayer* ancestorLayer) const
+LayoutRect RenderLayerCompositor::calculateCompositedBounds(const RenderLayer* layer, const RenderLayer* ancestorLayer) const
 {
     if (!canBeComposited(layer))
-        return IntRect();
+        return LayoutRect();
 
     RenderLayer::CalculateLayerBoundsFlags flags = RenderLayer::DefaultCalculateLayerBoundsFlags | RenderLayer::ExcludeHiddenDescendants | RenderLayer::DontConstrainForMask;
 #if HAVE(COMPOSITOR_FILTER_OUTSETS)