mus: Let clients set the cursor of their window.

components/mus/ws/event_dispatcher.h

Index: components/mus/ws/event_dispatcher.h
diff --git a/components/mus/ws/event_dispatcher.h b/components/mus/ws/event_dispatcher.h
index bbd2badce05cc8188c60cb9e6f660d5cc5e29568..1ee39735e2e8a0274a1ce8aa2c730acd0478a82a 100644
--- a/components/mus/ws/event_dispatcher.h
+++ b/components/mus/ws/event_dispatcher.h
@@ -33,6 +33,11 @@ class EventDispatcher : public ServerWindowObserver {
 
   void set_surface_id(cc::SurfaceId surface_id) { surface_id_ = surface_id; }
 
+  // Retrieves the ServerWindow of the last mouse move.

[sky, 2015/12/01 21:48:00]

Your code is setting for any pointer event, not just mouse. If you only want
mouse then you need to update the code.

[Elliot Glaysher, 2015/12/02 20:01:32]

Filtered on PointerKind here and in the dispatching code.

+  ServerWindow* last_targeted_window() const {
+    return last_pointer_target_window_;
+  }
+
   void AddAccelerator(uint32_t id, mojom::EventMatcherPtr event_matcher);
   void RemoveAccelerator(uint32_t id);
 
@@ -91,6 +96,7 @@ class EventDispatcher : public ServerWindowObserver {
 
   EventDispatcherDelegate* delegate_;
   ServerWindow* root_;
+  ServerWindow* last_pointer_target_window_;
 
   cc::SurfaceId surface_id_;