mus: Change PointerWatcher to observe all pointer events, with moves optional.

services/ui/demo/mus_demo.h

Index: services/ui/demo/mus_demo.h
diff --git a/services/ui/demo/mus_demo.h b/services/ui/demo/mus_demo.h
index 8957cc4f54fa4eeaa69a26ed8bfe70836ec81fe5..fc425f1f36142187d06536076015b042518a0a54 100644
--- a/services/ui/demo/mus_demo.h
+++ b/services/ui/demo/mus_demo.h
@@ -41,7 +41,8 @@ class MusDemo : public shell::Service,
   // WindowTreeClientDelegate:
   void OnEmbed(Window* root) override;
   void OnDidDestroyClient(WindowTreeClient* client) override;
-  void OnEventObserved(const Event& event, Window* target) override;
+  void OnPointerEventObserved(const PointerEvent& event,
+                              Window* target) override;
 
   // WindowManagerDelegate:
   void SetWindowManagerClient(WindowManagerClient* client) override;