mus: Implement interwindow drag and drop

services/ui/ws/window_tree.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_TREE_H_
 #define SERVICES_UI_WS_WINDOW_TREE_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 175 matching lines @@
   // required.
   void OnAccelerator(uint32_t accelerator_id,
                      const ui::Event& event,
                      bool needs_ack);
 
   // Called when |tree|'s jankiness changes (see janky_ for definition).
   // Notifies the window manager client so it can update UI for the affected
   // window(s).
   void ClientJankinessChanged(WindowTree* tree);
 
+  // The following methods send drag and drop messages to the client and return
+  // their results through the passed in callback.
+  void PerformOnDragEnter(
+      const ServerWindow* window,
+      mojo::Map<mojo::String, mojo::Array<uint8_t>> mime_data,
+      uint32_t key_state,
+      const gfx::Point& cursor_offset,
+      uint32_t effect_bitmask,
+      const base::Callback<void(uint32_t)>& callback);
+  void PerformOnDragOver(const ServerWindow* window,
+                         uint32_t key_state,
+                         const gfx::Point& cursor_offset,
+                         uint32_t effect_bitmask,
+                         const base::Callback<void(uint32_t)>& callback);
+  void PerformOnDragLeave(const ServerWindow* window);
+  void PerformOnDragDrop(const ServerWindow* window,
+                         uint32_t key_state,
+                         const gfx::Point& cursor_offset,
+                         uint32_t effect_bitmask,
+                         const base::Callback<void(uint32_t)>& callback);
+
   // The following methods are invoked after the corresponding change has been
   // processed. They do the appropriate bookkeeping and update the client as
   // necessary.
   void ProcessWindowBoundsChanged(const ServerWindow* window,
                                   const gfx::Rect& old_bounds,
                                   const gfx::Rect& new_bounds,
                                   bool originated_change);
   void ProcessClientAreaChanged(
       const ServerWindow* window,
       const gfx::Insets& new_client_area,
@@ skipping 205 matching lines @@
                                mojo::TextInputStatePtr state) override;
   void SetImeVisibility(Id transport_window_id,
                         bool visible,
                         mojo::TextInputStatePtr state) override;
   void OnWindowInputEventAck(uint32_t event_id,
                              mojom::EventResult result) override;
   void SetClientArea(
       Id transport_window_id,
       const gfx::Insets& insets,
       mojo::Array<gfx::Rect> transport_additional_client_areas) override;
+  void SetCanAcceptDrags(Id window_id, bool accepts_drags) override;
   void SetHitTestMask(Id transport_window_id,
                       const base::Optional<gfx::Rect>& mask) override;
   void GetWindowManagerClient(
       mojo::AssociatedInterfaceRequest<mojom::WindowManagerClient> internal)
       override;
   void GetCursorLocationMemory(const GetCursorLocationMemoryCallback& callback)
       override;
+  void PerformDragDrop(uint32_t change_id,
+                       uint32_t source_window_id,
+                       mojo::Map<mojo::String, mojo::Array<uint8_t>> drag_data,
+                       uint32_t drag_operation,
+                       const gfx::Point& cursor_offset,
+                       const SkBitmap& drag_representation) override;
   void PerformWindowMove(uint32_t change_id,
                          Id window_id,
                          ui::mojom::MoveLoopSource source,
                          const gfx::Point& cursor) override;
   void CancelWindowMove(Id window_id) override;
 
   // mojom::WindowManagerClient:
   void AddAccelerator(uint32_t id,
                       mojom::EventMatcherPtr event_matcher,
                       const AddAcceleratorCallback& callback) override;
@@ skipping 76 matching lines @@
       waiting_for_top_level_window_info_;
   bool embedder_intercepts_events_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTree);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_WINDOW_TREE_H_