Tab dragging as implemented as a mus API.

components/mus/public/cpp/tests/window_server_test_base.h

Index: components/mus/public/cpp/tests/window_server_test_base.h
diff --git a/components/mus/public/cpp/tests/window_server_test_base.h b/components/mus/public/cpp/tests/window_server_test_base.h
index ed244803026d9134561443843ae24e5e6c034d2b..2cc56c87189443892f8658073e52bc20c4dc6c5f 100644
--- a/components/mus/public/cpp/tests/window_server_test_base.h
+++ b/components/mus/public/cpp/tests/window_server_test_base.h
@@ -83,6 +83,10 @@ class WindowServerTestBase
                                   bool not_responding) override;
   void OnWmNewDisplay(Window* window, const display::Display& display) override;
   void OnAccelerator(uint32_t id, const ui::Event& event) override;
+  void OnWmPerformMoveLoop(uint32_t change_id,
+                           uint32_t window_id,
+                           const gfx::Point& cursor_location) override;
+  void OnWmCancelMoveLoop(uint32_t window_id) override;
 
   // InterfaceFactory<WindowTreeClient>:
   void Create(shell::Connection* connection,