mus: Disregard windows that explicitly set can_accept_events to be false when sending events.

services/ui/ws/window_tree.h

Index: services/ui/ws/window_tree.h
diff --git a/services/ui/ws/window_tree.h b/services/ui/ws/window_tree.h
index c975b06e0d61f82010c5c70599b19d540a1528c8..13d2ef2fe373ba5daa9bc13a270cae9552f59e6f 100644
--- a/services/ui/ws/window_tree.h
+++ b/services/ui/ws/window_tree.h
@@ -167,6 +167,7 @@ class WindowTree : public mojom::WindowTree,
   bool SetWindowVisibility(const ClientWindowId& window_id, bool visible);
   bool SetWindowOpacity(const ClientWindowId& window_id, float opacity);
   bool SetFocus(const ClientWindowId& window_id);
+  void SetAcceptEvents(Id transport_window_id, bool accept_events) override;
   bool Embed(const ClientWindowId& window_id,
              mojom::WindowTreeClientPtr client,
              uint32_t flags);