Wires up drag/drop for aura-mus

services/ui/ws/drag_controller.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/drag_controller.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "services/ui/public/interfaces/cursor.mojom.h"
@@ skipping 193 matching lines @@
   WindowState& state = window_state_[window];
   if (!state.observed) {
     state.observed = true;
     window->AddObserver(this);
   }
 }
 
 void DragController::QueueOperation(ServerWindow* window,
                                     OperationType type,
                                     uint32_t event_flags,
-                                    gfx::Point screen_position) {
+                                    const gfx::Point& screen_position) {
   // If this window doesn't have the mime data, send it.
   DragTargetConnection* connection = source_->GetDragTargetForWindow(window);
   if (connection != source_connection_ &&
       !base::ContainsKey(called_on_drag_mime_types_, connection)) {
     connection->PerformOnDragDropStart(mime_data_.Clone());
     called_on_drag_mime_types_.insert(connection);
   }
 
   WindowState& state = window_state_[window];
   // Set the queued operation to the incoming.
@@ skipping 99 matching lines @@
 
   if (source_window_ == window) {
     source_window_ = nullptr;
     // Our source window is being deleted, fail the drag.
     MessageDragCompleted(false, ui::mojom::kDropEffectNone);
   }
 }
 
 }  // namespace ws
 }  // namespace ui