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

services/navigation/view_impl.h

Index: services/navigation/view_impl.h
diff --git a/services/navigation/view_impl.h b/services/navigation/view_impl.h
index ad9b7edc13f1d77170958770349a03b816992419..f502bce19160b8ea637562efb70e17690e3b0a2b 100644
--- a/services/navigation/view_impl.h
+++ b/services/navigation/view_impl.h
@@ -82,7 +82,8 @@ class ViewImpl : public mojom::View,
   // ui::WindowTreeClientDelegate:
   void OnEmbed(ui::Window* root) override;
   void OnDidDestroyClient(ui::WindowTreeClient* client) override;
-  void OnEventObserved(const ui::Event& event, ui::Window* target) override;
+  void OnPointerEventObserved(const ui::PointerEvent& event,
+                              ui::Window* target) override;
 
   // views::WidgetDelegate:
   views::View* GetContentsView() override;