Revert of Don't rely on values computed as a side effect of paint.

Source/core/rendering/RenderLayerScrollableArea.cpp

Index: Source/core/rendering/RenderLayerScrollableArea.cpp
diff --git a/Source/core/rendering/RenderLayerScrollableArea.cpp b/Source/core/rendering/RenderLayerScrollableArea.cpp
index 83d02b4aa7ebf0b5e033e02c024ffb4da76bf434..f853c269513d06935c90b40684118bb58a9ec078 100644
--- a/Source/core/rendering/RenderLayerScrollableArea.cpp
+++ b/Source/core/rendering/RenderLayerScrollableArea.cpp
@@ -395,8 +395,8 @@
         bool onlyScrolledCompositedLayers = scrollsOverflow()
             && !layer()->hasVisibleNonLayerContent()
             && !layer()->hasNonCompositedChild()
-            && !m_box->isMarquee()
-            && layer()->renderer()->selectionRect().isEmpty();
+            && !layer()->hasBlockSelectionGapBounds()
+            && !m_box->isMarquee();
 
         if (usesCompositedScrolling() || onlyScrolledCompositedLayers)
             requiresRepaint = false;