mash: remove more shell/shelf WmWindow usage.

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 5474a60807bd25f09c38fe3d8634cf2e89b0edcc..125a25fb210c837f0ba4cda4e85d2d5dddd1c8fe 100644
--- a/ash/root_window_controller_unittest.cc
+++ b/ash/root_window_controller_unittest.cc
@@ -384,8 +384,7 @@ TEST_F(RootWindowControllerTest, MoveWindows_LockWindowsInUnified) {
 
 TEST_F(RootWindowControllerTest, ModalContainer) {
   UpdateDisplay("600x600");
-  RootWindowController* controller =
-      ShellPort::Get()->GetPrimaryRootWindowController();
+  RootWindowController* controller = Shell::GetPrimaryRootWindowController();
   EXPECT_TRUE(Shell::Get()->session_controller()->IsActiveUserSessionStarted());
   EXPECT_EQ(GetLayoutManager(controller, kShellWindowId_SystemModalContainer),
             controller->GetSystemModalLayoutManager(NULL));
@@ -426,8 +425,7 @@ TEST_F(RootWindowControllerTest, ModalContainerNotLoggedInLoggedIn) {
   EXPECT_EQ(0, session_controller->NumberOfLoggedInUsers());
   EXPECT_FALSE(session_controller->IsActiveUserSessionStarted());
 
-  RootWindowController* controller =
-      ShellPort::Get()->GetPrimaryRootWindowController();
+  RootWindowController* controller = Shell::GetPrimaryRootWindowController();
   EXPECT_EQ(
       GetLayoutManager(controller, kShellWindowId_LockSystemModalContainer),
       controller->GetSystemModalLayoutManager(NULL));
@@ -459,8 +457,7 @@ TEST_F(RootWindowControllerTest, ModalContainerNotLoggedInLoggedIn) {
 
 TEST_F(RootWindowControllerTest, ModalContainerBlockedSession) {
   UpdateDisplay("600x600");
-  RootWindowController* controller =
-      ShellPort::Get()->GetPrimaryRootWindowController();
+  RootWindowController* controller = Shell::GetPrimaryRootWindowController();
   aura::Window* lock_container =
       controller->GetContainer(kShellWindowId_LockScreenContainer);
   for (int block_reason = FIRST_BLOCK_REASON;