Standardize Screen::GetCursorScreenPoint() on Env::last_mouse_location

ui/views/mus/screen_mus.h

Index: ui/views/mus/screen_mus.h
diff --git a/ui/views/mus/screen_mus.h b/ui/views/mus/screen_mus.h
index a2df7e61e73d98df93e667862c063c247a4bc6b0..d3c4cf0463d9787abfb1ee860b3e07c9f3c5cd34 100644
--- a/ui/views/mus/screen_mus.h
+++ b/ui/views/mus/screen_mus.h
@@ -23,7 +23,6 @@ class VIEWS_MUS_EXPORT ScreenMus
     : public display::ScreenBase,
       public NON_EXPORTED_BASE(ui::mojom::DisplayManagerObserver) {
  public:
-  // |delegate| can be nullptr.
   explicit ScreenMus(ScreenMusDelegate* delegate);
   ~ScreenMus() override;
 
@@ -44,7 +43,7 @@ class VIEWS_MUS_EXPORT ScreenMus
   void OnDisplayRemoved(int64_t display_id) override;
   void OnPrimaryDisplayChanged(int64_t primary_display_id) override;
 
-  ScreenMusDelegate* delegate_;  // Can be nullptr.
+  ScreenMusDelegate* delegate_;
   ui::mojom::DisplayManagerPtr display_manager_;
   mojo::Binding<ui::mojom::DisplayManagerObserver>
       display_manager_observer_binding_;