Fix r475187 which is a bad revert.

ash/wm/maximize_mode/maximize_mode_window_state.cc

Index: ash/wm/maximize_mode/maximize_mode_window_state.cc
diff --git a/ash/wm/maximize_mode/maximize_mode_window_state.cc b/ash/wm/maximize_mode/maximize_mode_window_state.cc
index be0df25e4622ee82c3aaee2105c6bedab54ba485..ff07cffd04b089698256dce8556aeef1271adc0d 100644
--- a/ash/wm/maximize_mode/maximize_mode_window_state.cc
+++ b/ash/wm/maximize_mode/maximize_mode_window_state.cc
@@ -307,7 +307,7 @@ void MaximizeModeWindowState::UpdateWindow(wm::WindowState* window_state,
       old_state_type == wm::WINDOW_STATE_TYPE_TRUSTED_PINNED ||
       target_state == wm::WINDOW_STATE_TYPE_TRUSTED_PINNED) {
     Shell::Get()->screen_pinning_controller()->SetPinnedWindow(
-        WmWindow::Get(window_state->window()));
+        window_state->window());
   }
 
   if ((window_state->window()->layer()->GetTargetVisibility() ||