Fix pixel snapping issues when layers become composited

Source/core/rendering/RenderLayerCompositor.h

Index: Source/core/rendering/RenderLayerCompositor.h
diff --git a/Source/core/rendering/RenderLayerCompositor.h b/Source/core/rendering/RenderLayerCompositor.h
index 31d715a066ecf335b7b5d5686c699f5db0135e87..09ddbb84db42c073429ef2328472ae8e972f7e68 100644
--- a/Source/core/rendering/RenderLayerCompositor.h
+++ b/Source/core/rendering/RenderLayerCompositor.h
@@ -116,7 +116,7 @@ public:
 
     // Return the bounding box required for compositing layer and its childern, relative to ancestorLayer.
     // If layerBoundingBox is not 0, on return it contains the bounding box of this layer only.
-    IntRect calculateCompositedBounds(const RenderLayer*, const RenderLayer* ancestorLayer) const;
+    LayoutRect calculateCompositedBounds(const RenderLayer*, const RenderLayer* ancestorLayer) const;
 
     // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
     void repaintOnCompositingChange(RenderLayer*);