Moves Shell::ShowShelf() to WmShell

ash/test/test_session_state_delegate.cc

Index: ash/test/test_session_state_delegate.cc
diff --git a/ash/test/test_session_state_delegate.cc b/ash/test/test_session_state_delegate.cc
index 9c39a9e43b5c3a0c5062aee75f9c67acc0230373..9d09bc8a852dc6d2c8ba9911dc29fa1a68fe7064 100644
--- a/ash/test/test_session_state_delegate.cc
+++ b/ash/test/test_session_state_delegate.cc
@@ -166,7 +166,7 @@ void TestSessionStateDelegate::SetHasActiveUser(bool has_active_user) {
     session_state_ = SESSION_STATE_LOGIN_PRIMARY;
   } else {
     session_state_ = SESSION_STATE_ACTIVE;
-    Shell::GetInstance()->ShowShelf();
+    WmShell::Get()->ShowShelf();
   }
 }