Wires up drag/drop for aura-mus

ui/aura/mus/drag_drop_controller_mus.h

Index: ui/aura/mus/drag_drop_controller_mus.h
diff --git a/ui/aura/mus/drag_drop_controller_mus.h b/ui/aura/mus/drag_drop_controller_mus.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b4efa81b4a97bf5d340161b5740ae0bb5b9b103
--- /dev/null
+++ b/ui/aura/mus/drag_drop_controller_mus.h
@@ -0,0 +1,114 @@
+// 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.
+
+#ifndef UI_AURA_MUS_DRAG_DROP_CONTROLLER_MUS_H_
+#define UI_AURA_MUS_DRAG_DROP_CONTROLLER_MUS_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "ui/aura/client/drag_drop_client.h"
+#include "ui/aura/window_tracker.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+
+namespace ui {
+class DropTargetEvent;
+class LocatedEvent;
+class OSExchangeData;
+
+namespace mojom {
+class WindowTree;
+}
+}
+
+namespace aura {
+
+class DragDropControllerHost;
+class WindowMus;
+
+// DragDropControllerMus acts as the DragDropClient for aura as well as
+// handling all drag operations from the server. Drag operations are forwarded
+// to the client::DragDropDelegate set on the target Window.
+class DragDropControllerMus : public client::DragDropClient {
+ public:
+  DragDropControllerMus(DragDropControllerHost* drag_drop_controller_host,
+                        ui::mojom::WindowTree* window_tree);
+  ~DragDropControllerMus() override;
+
+  // Returns true if a drag was initiated and |id| identifies the change if of
+  // the drag.
+  bool DoesChangeIdMatchDragChangeId(uint32_t id) const;
+
+  // Forwarded from WindowTreeClient. These correspond to the functions of the
+  // same name defined in ui::mojom::WindowTreeClient.
+  void OnDragDropStart(std::map<std::string, std::vector<uint8_t>> data);
+  uint32_t OnDragEnter(WindowMus* window,
+                       uint32_t event_flags,
+                       const gfx::Point& screen_location,
+                       uint32_t effect_bitmask);
+  uint32_t OnDragOver(WindowMus* window,
+                      uint32_t event_flags,
+                      const gfx::Point& screen_location,
+                      uint32_t effect_bitmask);
+  void OnDragLeave(WindowMus* window);
+  uint32_t OnCompleteDrop(WindowMus* window,
+                          uint32_t event_flags,
+                          const gfx::Point& screen_location,
+                          uint32_t effect_bitmask);
+  void OnPerformDragDropCompleted(uint32_t action_taken);
+  void OnDragDropDone();
+
+  // Overridden from client::DragDropClient:
+  int StartDragAndDrop(const ui::OSExchangeData& data,
+                       Window* root_window,
+                       Window* source_window,
+                       const gfx::Point& screen_location,
+                       int drag_operations,
+                       ui::DragDropTypes::DragEventSource source) override;
+  void DragCancel() override;
+  bool IsDragDropInProgress() override;
+
+ private:
+  struct CurrentDragState;
+
+  // Called from OnDragEnter() and OnDragOver().
+  uint32_t HandleDragEnterOrOver(WindowMus* window,
+                                 uint32_t event_flags,
+                                 const gfx::Point& screen_location,
+                                 uint32_t effect_bitmask,
+                                 bool is_enter);
+
+  std::unique_ptr<ui::DropTargetEvent> CreateDropTargetEvent(
+      Window* window,
+      uint32_t event_flags,
+      const gfx::Point& screen_location,
+      uint32_t effect_bitmask);
+
+  DragDropControllerHost* drag_drop_controller_host_;
+
+  ui::mojom::WindowTree* window_tree_;
+
+  // State related to being the initiator of a drag started with
+  // PerformDragDrop(). If non-null a drag was started by this client and is
+  // still in progress. This references a value declared on the stack in
+  // StartDragAndDrop().
+  CurrentDragState* current_drag_state_ = nullptr;
+
+  // The entire drag data payload. We receive this during the drag enter event
+  // and cache it so we don't send this multiple times. This value is reset when
+  // the drag is done.
+  std::unique_ptr<ui::OSExchangeData> os_exchange_data_;
+
+  // Used to track the current drop target.
+  WindowTracker drop_target_window_tracker_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragDropControllerMus);
+};
+
+}  // namespace aura
+
+#endif  // UI_AURA_MUS_DRAG_DROP_CONTROLLER_MUS_H_