mash: Convert virtual keyboard system tray item to wm common types

ash/common/wm_shell.cc

Index: ash/common/wm_shell.cc
diff --git a/ash/common/wm_shell.cc b/ash/common/wm_shell.cc
index e1078fa47c018ee5a7bb0aefe2a4914411eb8c61..c7376aeae2488984651e97c563c4d225ed401729 100644
--- a/ash/common/wm_shell.cc
+++ b/ash/common/wm_shell.cc
@@ -5,6 +5,7 @@
 #include "ash/common/wm_shell.h"
 
 #include "ash/common/focus_cycler.h"
+#include "ash/common/keyboard/keyboard_ui.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/chromeos/session/logout_confirmation_controller.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
@@ -56,6 +57,10 @@ bool WmShell::IsSystemModalWindowOpen() {
   return false;
 }
 
+void WmShell::SetKeyboardUI(std::unique_ptr<KeyboardUI> keyboard_ui) {
+  keyboard_ui_ = std::move(keyboard_ui);
+}
+
 void WmShell::SetSystemTrayDelegate(
     std::unique_ptr<SystemTrayDelegate> delegate) {
   DCHECK(delegate);