Make squashing work with subpixel layout

LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt

Index: LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt
diff --git a/LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt b/LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt
index caf2a38359ba78fb3fec5c0fbdd999ffd41b8be3..ea85721329cf2666afb58b363281febf52b18f48 100644
--- a/LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt
+++ b/LayoutTests/compositing/squashing/squash-transform-repainting-child-expected.txt
@@ -18,7 +18,7 @@ CASE 1, original layer tree
             )
             (GraphicsLayer
               (position -1.00 -1.00)
-              (bounds 280.72 280.72)
+              (bounds 281.00 281.00)
               (drawsContent 1)
             )
           )
@@ -47,12 +47,12 @@ CASE 2, hovering over the outer div
             )
             (GraphicsLayer
               (position -1.00 -1.00)
-              (bounds 280.72 280.72)
+              (bounds 281.00 281.00)
               (drawsContent 1)
               (repaint rects
-                (rect 0.00 0.00 141.00 141.00)
-                (rect 0.00 0.00 141.00 141.00)
-                (rect 0.00 0.00 141.00 141.00)
+                (rect 0.00 0.00 142.00 142.00)
+                (rect 0.00 0.00 142.00 142.00)
+                (rect 0.00 0.00 142.00 142.00)
               )
             )
           )
@@ -81,15 +81,15 @@ CASE 3, hovering over the inner div
             )
             (GraphicsLayer
               (position -1.00 -1.00)
-              (bounds 280.72 280.72)
+              (bounds 281.00 281.00)
               (drawsContent 1)
               (repaint rects
-                (rect 0.00 0.00 141.00 141.00)
-                (rect 0.00 0.00 141.00 141.00)
-                (rect 0.00 0.00 141.00 141.00)
-                (rect 31.00 31.00 71.00 71.00)
-                (rect 31.00 31.00 71.00 71.00)
-                (rect 31.00 31.00 71.00 71.00)
+                (rect 0.00 0.00 142.00 142.00)
+                (rect 0.00 0.00 142.00 142.00)
+                (rect 0.00 0.00 142.00 142.00)
+                (rect 32.00 32.00 71.00 71.00)
+                (rect 32.00 32.00 71.00 71.00)
+                (rect 32.00 32.00 71.00 71.00)
               )
             )
           )