aura-mus: wire up drag and drop.

ui/aura/mus/drag_drop_controller_mus.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 "ui/aura/mus/drag_drop_controller_mus.h"
 
 #include <map>
 #include <string>
 #include <vector>
 
@@ skipping 119 matching lines @@
     Window* source_window,
     const gfx::Point& screen_location,
     int drag_operations,
     ui::DragDropTypes::DragEventSource source) {
   DCHECK(!current_drag_state_);
 
   // TODO(erg): Pass |cursor_location| and |bitmap| in PerformDragDrop() when
   // we start showing an image representation of the drag under he cursor.
 
   base::RunLoop run_loop;
-  WindowMus* source_window_mus = WindowMus::Get(source_window);
+  WindowMus* root_window_mus = WindowMus::Get(root_window);
   const uint32_t change_id =
-      drag_drop_controller_host_->CreateChangeIdForDrag(source_window_mus);
-  CurrentDragState current_drag_state = {source_window_mus->server_id(),
+      drag_drop_controller_host_->CreateChangeIdForDrag(root_window_mus);
+  CurrentDragState current_drag_state = {root_window_mus->server_id(),
                                          change_id, ui::mojom::kDropEffectNone,
                                          data, run_loop.QuitClosure()};
   base::AutoReset<CurrentDragState*> resetter(&current_drag_state_,
                                               &current_drag_state);
+
+  base::MessageLoop* loop = base::MessageLoop::current();
+  base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
+
   std::map<std::string, std::vector<uint8_t>> drag_data =
       static_cast<const aura::OSExchangeDataProviderMus&>(data.provider())
           .GetData();
-  window_tree_->PerformDragDrop(change_id, source_window_mus->server_id(),
+  window_tree_->PerformDragDrop(change_id, root_window_mus->server_id(),
                                 mojo::MapToUnorderedMap(drag_data),
                                 drag_operations);
 
-  base::MessageLoop* loop = base::MessageLoop::current();
-  base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
   run_loop.Run();
 
   return current_drag_state.completed_action;
 }
 
 void DragDropControllerMus::DragCancel() {
   DCHECK(current_drag_state_);
   // Server will clean up drag and fail the in-flight change.
   window_tree_->CancelDragDrop(current_drag_state_->window_id);
 }
@@ skipping 39 matching lines @@
   std::unique_ptr<ui::DropTargetEvent> event =
       base::MakeUnique<ui::DropTargetEvent>(
           current_drag_state_ ? current_drag_state_->drag_data
                               : *(os_exchange_data_.get()),
           location, root_location, effect_bitmask);
   event->set_flags(event_flags);
   return event;
 }
 
 }  // namespace aura