[mus+ash] Removes WmWindow from ash/wm/screen_pinning_controller.h

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index b758bd8cc97dd7a805292af778e4ff600a9aa192..1ddf282c66db499bd490bedf2394572def36d3f4 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -518,7 +518,7 @@ void Shell::NotifyFullscreenStateChanged(bool is_fullscreen,
     observer.OnFullscreenStateChanged(is_fullscreen, root_window);
 }
 
-void Shell::NotifyPinnedStateChanged(WmWindow* pinned_window) {
+void Shell::NotifyPinnedStateChanged(aura::Window* pinned_window) {
   for (auto& observer : shell_observers_)
     observer.OnPinnedStateChanged(pinned_window);
 }