mash: remove more shell/shelf WmWindow usage.

chrome/browser/chromeos/login/login_browsertest.cc

Index: chrome/browser/chromeos/login/login_browsertest.cc
diff --git a/chrome/browser/chromeos/login/login_browsertest.cc b/chrome/browser/chromeos/login/login_browsertest.cc
index feef0793623a0c482e196b5351793a3a6767ab31..0ea474b3f57631de19858badb4fba00ebf87aea5 100644
--- a/chrome/browser/chromeos/login/login_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_browsertest.cc
@@ -329,8 +329,7 @@ class ActiveDirectoryLoginTest : public LoginManagerTest {
 void TestSystemTrayIsVisible(bool otr) {
   ash::SystemTray* tray = ash::Shell::Get()->GetPrimarySystemTray();
   aura::Window* primary_win = ash::Shell::GetPrimaryRootWindow();
-  ash::WmWindow* wm_primary_win = ash::WmWindow::Get(primary_win);
-  ash::WmShelf* wm_shelf = ash::WmShelf::ForWindow(wm_primary_win);
+  ash::WmShelf* wm_shelf = ash::WmShelf::ForWindow(primary_win);
   SCOPED_TRACE(testing::Message()
                << "ShelfVisibilityState=" << wm_shelf->GetVisibilityState()
                << " ShelfAutoHideBehavior=" << wm_shelf->auto_hide_behavior());