aura-mus: add a drag representation image.

services/ui/ws/window_manager_client_unittest.cc

Index: services/ui/ws/window_manager_client_unittest.cc
diff --git a/services/ui/ws/window_manager_client_unittest.cc b/services/ui/ws/window_manager_client_unittest.cc
index ce5e9dd2af470d1c69f003f3dde1a15f49164037..6f2211a09ab845961b8a6b0bd0ca06c6492f92d3 100644
--- a/services/ui/ws/window_manager_client_unittest.cc
+++ b/services/ui/ws/window_manager_client_unittest.cc
@@ -63,6 +63,12 @@ class TestWindowManagerDelegate : public aura::WindowManagerDelegate {
   }
   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 {}