Clean up some ash constants.

ash/root_window_controller_unittest.cc

Index: ash/root_window_controller_unittest.cc
diff --git a/ash/root_window_controller_unittest.cc b/ash/root_window_controller_unittest.cc
index 3671f30b9ce7eb6b00706bdfeec8e5b62947154f..3992e8d4f8b4da4f49f771b77ceaba080dc40bbe 100644
--- a/ash/root_window_controller_unittest.cc
+++ b/ash/root_window_controller_unittest.cc
@@ -219,8 +219,8 @@ TEST_F(RootWindowControllerTest, MoveWindows_Basic) {
   EXPECT_EQ("100,20 100x100",
             normal->GetNativeView()->GetBoundsInRootWindow().ToString());
 
-  // Maximized area on primary display has 47px for non-md and 48px for md
-  // (defined in SHELF_SIZE) inset at the bottom.
+  // Maximized area on primary display has 48px for inset at the bottom
+  // (kShelfSize).
 
   // First clear fullscreen status, since both fullscreen and maximized windows
   // share the same desktop workspace, which cancels the shelf status.