mash: Move directly linked NewWindowDelegate to mojom::NewWindowClient.

ash/common/test/wm_shell_test_api.cc

Index: ash/common/test/wm_shell_test_api.cc
diff --git a/ash/common/test/wm_shell_test_api.cc b/ash/common/test/wm_shell_test_api.cc
index 39305eaf885b3a2a08b839fb8c795b02124b8044..fc37d56bd9d6eea36f82b8dd985ba8c757e41b93 100644
--- a/ash/common/test/wm_shell_test_api.cc
+++ b/ash/common/test/wm_shell_test_api.cc
@@ -4,8 +4,11 @@
 
 #include "ash/common/test/wm_shell_test_api.h"
 
+#include <utility>
+
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wm_shell.h"
+#include "ash/public/interfaces/new_window.mojom.h"
 
 namespace ash {
 
@@ -18,4 +21,9 @@ void WmShellTestApi::SetSystemTrayDelegate(
   WmShell::Get()->SetSystemTrayDelegate(std::move(delegate));
 }
 
+void WmShellTestApi::SetNewWindowClient(
+    std::unique_ptr<mojom::NewWindowClient> client) {
+  WmShell::Get()->new_window_client_ = std::move(client);
+}
+
 }  // namespace ash