aura-mus: add a drag representation image.

services/ui/ws/window_server_test_base.h

Index: services/ui/ws/window_server_test_base.h
diff --git a/services/ui/ws/window_server_test_base.h b/services/ui/ws/window_server_test_base.h
index c8160485d2eb05f3c39ec04e55a6ba75c19ba39a..b26c0ec7ae526e8fc9f675775767428835ddf887 100644
--- a/services/ui/ws/window_server_test_base.h
+++ b/services/ui/ws/window_server_test_base.h
@@ -100,6 +100,12 @@ class WindowServerTestBase
       std::map<std::string, std::vector<uint8_t>>* properties) override;
   void OnWmClientJankinessChanged(const std::set<aura::Window*>& client_windows,
                                   bool not_responding) override;
+  void OnWmBuildDragImage(const gfx::Point& cursor_location,
+                          const SkBitmap& drag_image,
+                          const gfx::Vector2d& drag_image_offset,
+                          ui::mojom::DragEventSource source) override {}
+  void OnWmMoveDragImage(const gfx::Point& cursor_location) override {}
+  void OnWmDestroyDragImage() override {}
   void OnWmWillCreateDisplay(const display::Display& display) override;
   void OnWmNewDisplay(std::unique_ptr<aura::WindowTreeHostMus> window_tree_host,
                       const display::Display& display) override;