mus: Implement interwindow drag and drop

services/ui/ws/window_manager_state.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/window_manager_state.h"
 
 #include <utility>
 
 #include "base/memory/weak_ptr.h"
 #include "services/shell/public/interfaces/connector.mojom.h"
@@ skipping 137 matching lines @@
 
 void WindowManagerState::ReleaseCaptureBlockedByModalWindow(
     const ServerWindow* modal_window) {
   event_dispatcher_.ReleaseCaptureBlockedByModalWindow(modal_window);
 }
 
 void WindowManagerState::ReleaseCaptureBlockedByAnyModalWindow() {
   event_dispatcher_.ReleaseCaptureBlockedByAnyModalWindow();
 }
 
+void WindowManagerState::SetDragDropSourceWindow(
+    DragSource* drag_source,
+    ServerWindow* window,
+    DragTargetConnection* source_connection,
+    int32_t drag_pointer,
+    mojo::Map<mojo::String, mojo::Array<uint8_t>> drag_data,
+    uint32_t drag_operation) {
+  event_dispatcher_.SetDragDropSourceWindow(
+      drag_source, window, source_connection, drag_pointer,
+      std::move(drag_data), drag_operation);
+}
+
+void WindowManagerState::EndDragDrop() {
+  event_dispatcher_.EndDragDrop();
+}
+
 void WindowManagerState::AddSystemModalWindow(ServerWindow* window) {
   DCHECK(!window->transient_parent());
   event_dispatcher_.AddSystemModalWindow(window);
 }
 
 const UserId& WindowManagerState::user_id() const {
   return window_tree_->user_id();
 }
 
 void WindowManagerState::OnWillDestroyTree(WindowTree* tree) {
+  event_dispatcher_.OnWillDestroyDragTargetConnection(tree);
+
   if (tree_awaiting_input_ack_ != tree)
     return;
 
   // The WindowTree is dying. So it's not going to ack the event.
   // If the dying tree matches the root |tree_| marked as handled so we don't
   // notify it of accelerators.
   OnEventAck(tree_awaiting_input_ack_, tree == window_tree_
                                            ? mojom::EventResult::HANDLED
                                            : mojom::EventResult::UNHANDLED);
 }
@@ skipping 384 matching lines @@
   return display_root->root();
 }
 
 void WindowManagerState::OnEventTargetNotFound(const ui::Event& event) {
   window_server()->SendToPointerWatchers(event, user_id(), nullptr, /* window */
                                          nullptr /* ignore_tree */);
 }
 
 }  // namespace ws
 }  // namespace ui