Auto-rebaseline for r171962

LayoutTests/platform/mac/virtual/softwarecompositing/overflow/do-not-opt-non-stacking-context-descendants-into-composited-scrolling-expected.txt

 This test ensures that the descendants of children of non-stacking context overflow-scroll divs do not get promoted needlessly. Only the immediate child of an overflow-scroll div, or an unclipped descendant, need to be promoted.
 
 (GraphicsLayer
   (bounds 1832.00 1682.00)
   (children 1
     (GraphicsLayer
       (bounds 1832.00 1682.00)
       (contentsOpaque 1)
       (drawsContent 1)
-      (children 4
+      (children 3
         (GraphicsLayer
           (position 28.00 320.00)
           (bounds 402.00 402.00)
           (drawsContent 1)
           (children 4
             (GraphicsLayer
               (position 1.00 1.00)
               (bounds 385.00 385.00)
               (children 1
                 (GraphicsLayer
@@ skipping 11 matching lines @@
               (bounds 15.00 385.00)
             )
             (GraphicsLayer
               (position 386.00 386.00)
               (bounds 15.00 15.00)
               (drawsContent 1)
             )
           )
         )
         (GraphicsLayer
-          (position 39.00 331.00)
-          (bounds 180.00 300.00)
+          (children 2
+            (GraphicsLayer
+              (position 39.00 331.00)
+              (bounds 180.00 300.00)
+              (contentsOpaque 1)
+              (drawsContent 1)
+              (backgroundColor #808080)
+            )
+            (GraphicsLayer
+              (position 39.00 641.00)
+              (bounds 180.00 620.00)
+              (drawsContent 1)
+            )
+          )
+        )
+        (GraphicsLayer
+          (position 39.00 441.00)
+          (bounds 100.00 100.00)
           (contentsOpaque 1)
           (drawsContent 1)
-          (backgroundColor #808080)
-        )
-        (GraphicsLayer
-          (position 39.00 961.00)
-          (bounds 180.00 300.00)
-          (contentsOpaque 1)
-          (drawsContent 1)
-          (backgroundColor #0000FF)
-        )
-        (GraphicsLayer
-          (position 39.00 641.00)
-          (bounds 180.00 300.00)
-          (contentsOpaque 1)
-          (drawsContent 1)
-          (backgroundColor #808080)
-          (children 1
-            (GraphicsLayer
-              (position 0.00 -200.00)
-              (bounds 100.00 100.00)
-              (contentsOpaque 1)
-              (drawsContent 1)
-              (backgroundColor #000000)
-            )
-          )
+          (backgroundColor #000000)
         )
       )
     )
   )
 )