mus: Implement interwindow drag and drop

services/ui/ws/window_server.h

 // Copyright 2014 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.
 
 #ifndef SERVICES_UI_WS_WINDOW_SERVER_H_
 #define SERVICES_UI_WS_WINDOW_SERVER_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
+#include "base/optional.h"
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "services/ui/clipboard/clipboard_impl.h"
 #include "services/ui/public/interfaces/window_manager_window_tree_factory.mojom.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 #include "services/ui/public/interfaces/window_tree_host.mojom.h"
 #include "services/ui/surfaces/surfaces_state.h"
 #include "services/ui/ws/display.h"
 #include "services/ui/ws/display_manager_delegate.h"
 #include "services/ui/ws/ids.h"
@@ skipping 183 matching lines @@
                      ServerWindow* window,
                      WindowTree* initiator,
                      const gfx::Rect& revert_bounds);
   void EndMoveLoop();
   uint32_t GetCurrentMoveLoopChangeId();
   ServerWindow* GetCurrentMoveLoopWindow();
   WindowTree* GetCurrentMoveLoopInitiator();
   gfx::Rect GetCurrentMoveLoopRevertBounds();
   bool in_move_loop() const { return !!current_move_loop_; }
 
+  void StartDragLoop(uint32_t change_id);
+  void EndDragLoop();
+  uint32_t GetCurrentDragLoopChangeId();
+  bool in_drag_loop() const { return current_drag_loop_.has_value(); }
+
  private:
   struct CurrentMoveLoopState;
   friend class Operation;
 
   using WindowTreeMap =
       std::map<ClientSpecificId, std::unique_ptr<WindowTree>>;
   using UserActivityMonitorMap =
       std::map<UserId, std::unique_ptr<UserActivityMonitor>>;
   using UserClipboardMap =
       std::map<UserId, std::unique_ptr<ui::clipboard::ClipboardImpl>>;
@@ skipping 100 matching lines @@
   WindowServerDelegate* delegate_;
 
   // State for rendering into a Surface.
   scoped_refptr<ui::SurfacesState> surfaces_state_;
 
   // ID to use for next WindowTree.
   ClientSpecificId next_client_id_;
 
   std::unique_ptr<DisplayManager> display_manager_;
 
+  base::Optional<uint32_t> current_drag_loop_;
+
   std::unique_ptr<CurrentMoveLoopState> current_move_loop_;
 
   // Set of WindowTrees.
   WindowTreeMap tree_map_;
 
   // If non-null then we're processing a client operation. The Operation is
   // not owned by us (it's created on the stack by WindowTree).
   Operation* current_operation_;
 
   bool in_destructor_;
@@ skipping 13 matching lines @@
 
   WindowManagerWindowTreeFactorySet window_manager_window_tree_factory_set_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowServer);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_WINDOW_SERVER_H_