mash: remove more shell/shelf WmWindow usage.

ash/sticky_keys/sticky_keys_overlay_unittest.cc

Index: ash/sticky_keys/sticky_keys_overlay_unittest.cc
diff --git a/ash/sticky_keys/sticky_keys_overlay_unittest.cc b/ash/sticky_keys/sticky_keys_overlay_unittest.cc
index 576db82fb8045a1375fab10a4a1c370915d0069f..dcf60cb7adbdcbccd625bc2fc7a724f439592a2b 100644
--- a/ash/sticky_keys/sticky_keys_overlay_unittest.cc
+++ b/ash/sticky_keys/sticky_keys_overlay_unittest.cc
@@ -68,17 +68,13 @@ TEST_F(StickyKeysOverlayTest, OverlayNotDestroyedAfterDisplayRemoved) {
   // The overlay should belong to the secondary root window.
   StickyKeysOverlay overlay;
   views::Widget* overlay_widget = overlay.GetWidgetForTesting();
-  EXPECT_EQ(ShellPort::Get()
-                ->GetRootWindowForDisplayId(secondary_display_id)
-                ->aura_window(),
+  EXPECT_EQ(ShellPort::Get()->GetRootWindowForDisplayId(secondary_display_id),
             overlay_widget->GetNativeWindow()->GetRootWindow());
 
   // Removing the second display should move the overlay to the primary root
   // window.
   UpdateDisplay("1280x1024");
-  EXPECT_EQ(ShellPort::Get()
-                ->GetRootWindowForDisplayId(primary_display_id)
-                ->aura_window(),
+  EXPECT_EQ(ShellPort::Get()->GetRootWindowForDisplayId(primary_display_id),
             overlay_widget->GetNativeWindow()->GetRootWindow());
 
   overlay.SetModifierKeyState(ui::EF_SHIFT_DOWN, STICKY_KEY_STATE_ENABLED);