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

services/ui/public/cpp/window.h

Index: services/ui/public/cpp/window.h
diff --git a/services/ui/public/cpp/window.h b/services/ui/public/cpp/window.h
index c902e58eee4acff2e19626e1374ba64e0109ade0..fc5efd9eb419511e94ebba6c6767a080399af3c9 100644
--- a/services/ui/public/cpp/window.h
+++ b/services/ui/public/cpp/window.h
@@ -209,6 +209,9 @@ class Window {
   bool HasFocus() const;
   void SetCanFocus(bool can_focus);
 
+  // Sets whether this window accepts events.
+  void SetCanAcceptEvents(bool can_accept_events);
+
   // Embedding. See window_tree.mojom for details.
   void Embed(ui::mojom::WindowTreeClientPtr client, uint32_t flags = 0);
 
@@ -339,6 +342,10 @@ class Window {
   float opacity_;
   int64_t display_id_;
 
+  // Whether this window can accept events. Initialized to true to
+  // match ServerWindow.
+  bool can_accept_events_ = true;
+
   mojom::Cursor cursor_id_;
 
   SharedProperties properties_;