[RootLayerScrolls] Annotate non-fast-scroll regions to correct layer

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
index 53a5b52e56ef8910b481493d92f9a1e80fc891b9..43d74b9bcddbf05213d01f42072244948742e7b3 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
@@ -377,6 +377,8 @@ class CORE_EXPORT PaintLayerScrollableArea final
                             const ScrollAlignment& alignY,
                             ScrollType = ProgrammaticScroll) override;
 
+  ClientRectList* nonFastScrollableRects() const override;
+
   // Returns true if scrollable area is in the FrameView's collection of
   // scrollable areas. This can only happen if we're scrollable, visible to hit
   // test, and do in fact overflow. This means that 'overflow: hidden' or