mash: remove more shell/shelf WmWindow usage.

ash/wm/window_cycle_controller_unittest.cc

Index: ash/wm/window_cycle_controller_unittest.cc
diff --git a/ash/wm/window_cycle_controller_unittest.cc b/ash/wm/window_cycle_controller_unittest.cc
index 1e0e856ecce2763f0b59ae2f24a5bea442f98725..3c7bf3d08f3c56a94bac3f25ec2abf4dcbb090af 100644
--- a/ash/wm/window_cycle_controller_unittest.cc
+++ b/ash/wm/window_cycle_controller_unittest.cc
@@ -409,8 +409,7 @@ TEST_F(WindowCycleControllerTest, AlwaysOnTopMultipleRootWindows) {
   EXPECT_EQ(root_windows[0], window1->GetRootWindow());
 
   // Move the active root window to the secondary root and create two windows.
-  ScopedRootWindowForNewWindows root_for_new_windows(
-      WmWindow::Get(root_windows[1]));
+  ScopedRootWindowForNewWindows root_for_new_windows(root_windows[1]);
   std::unique_ptr<Window> window2(CreateTestWindowInShellWithId(2));
   EXPECT_EQ(root_windows[1], window2->GetRootWindow());