arc: Implement proper Arc window activation for task moving to front.

components/exo/wayland/server.cc

Index: components/exo/wayland/server.cc
diff --git a/components/exo/wayland/server.cc b/components/exo/wayland/server.cc
index ee3a25aa333b40c14033de982e02b5aa1aff6724..300e14a3520d65e6891d8b374bfac154477a1885 100644
--- a/components/exo/wayland/server.cc
+++ b/components/exo/wayland/server.cc
@@ -1519,6 +1519,10 @@ void remote_surface_unset_system_modal(wl_client* client,
   GetUserDataAs<ShellSurface>(resource)->SetSystemModal(false);
 }
 
+void remote_surface_activate(wl_client* client, wl_resource* resource) {
+  GetUserDataAs<ShellSurface>(resource)->Activate();
+}
+
 const struct zwp_remote_surface_v1_interface remote_surface_implementation = {
     remote_surface_destroy,
     remote_surface_set_app_id,
@@ -1535,7 +1539,8 @@ const struct zwp_remote_surface_v1_interface remote_surface_implementation = {
     remote_surface_set_title,
     remote_surface_set_top_inset,
     remote_surface_set_system_modal,
-    remote_surface_unset_system_modal};
+    remote_surface_unset_system_modal,
+    remote_surface_activate};
 
 ////////////////////////////////////////////////////////////////////////////////
 // notification_surface_interface:
@@ -1838,7 +1843,7 @@ const struct zwp_remote_shell_v1_interface remote_shell_implementation = {
     remote_shell_destroy, remote_shell_get_remote_surface,
     remote_shell_get_notification_surface};
 
-const uint32_t remote_shell_version = 8;
+const uint32_t remote_shell_version = 9;
 
 void bind_remote_shell(wl_client* client,
                        void* data,