MacViews: Implemented Drag & Drop

ui/base/dragdrop/drag_drop_types_mac.mm

+// 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/base/dragdrop/drag_drop_types.h"
+
+#import <Cocoa/Cocoa.h>
+
+namespace ui {
+
+uint64_t ui::DragDropTypes::DragOperationToNSDragOperation(int drag_operation) {
+  NSUInteger ns_drag_operation = NSDragOperationNone;
+
+  if (drag_operation & DRAG_LINK)
+    ns_drag_operation |= NSDragOperationLink;
+  if (drag_operation & DRAG_COPY)
+    ns_drag_operation |= NSDragOperationCopy;
+  if (drag_operation & DRAG_MOVE)
+    ns_drag_operation |= NSDragOperationMove;
+
+  return ns_drag_operation;
+}
+
+}  // namespace ui