[InputEvent] Support |deleteByDrag|, |insertFromDrop| and fire in sequential order

third_party/WebKit/Source/core/editing/commands/DragAndDropCommand.cpp

+// 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 "core/editing/commands/DragAndDropCommand.h"
+
+namespace blink {
+
+DragAndDropCommand::DragAndDropCommand(Document& document)
+    : CompositeEditCommand(document) {}
+
+bool DragAndDropCommand::isCommandGroupWrapper() const {
+  return true;
+}
+
+bool DragAndDropCommand::isDragAndDropCommand() const {
+  return true;
+}
+
+void DragAndDropCommand::doApply(EditingState*) {
+  // Do nothing. Should only register undo entry after combined with other commands.
+}
+
+InputEvent::InputType DragAndDropCommand::inputType() const {
+  return InputEvent::InputType::None;
+}
+
+}  // namespace blink