aura-mus: add a drag representation image.

services/ui/ws/drag_controller_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/ui/ws/drag_controller.h"
 
 #include <map>
 #include <memory>
 #include <queue>
 #include <utility>
@@ skipping 218 matching lines @@
     testing::Test::TearDown();
   }
 
   // Overridden from DragCursorUpdater:
   void OnDragCursorUpdated() override {
     if (drag_operation_)
       cursor_ = ui::mojom::Cursor(drag_operation_->current_cursor());
   }
 
   // Overridden from DragControllerSource:
+  void OnDragContinued(const gfx::Point& location) override {}
+
   void OnDragCompleted(bool success, uint32_t action_taken) override {
     drag_completed_action_ = action_taken;
     drag_completed_value_ = success;
   }
 
   ServerWindow* GetWindowById(const WindowId& id) override {
     auto it = server_window_by_id_.find(id);
     if (it == server_window_by_id_.end())
       return nullptr;
     return it->second;
@@ skipping 429 matching lines @@
 
   // Window 2 responding negatively to its queued messages shouldn't change the
   // cursor.
   window2->Respond(false);
 
   EXPECT_EQ(ui::mojom::Cursor::COPY, cursor());
 }
 
 }  // namespace ws
 }  // namespace ui