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

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

+// 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.
+
+#ifndef DragAndDropCommand_h
+#define DragAndDropCommand_h
+
+#include "core/editing/commands/CompositeEditCommand.h"
+
+namespace blink {
+
+// |DragAndDropCommand| is a dummy command. It doesn't do anything by itself, but will act as a catcher for the following |DeleteByDrag| and |InsertFromDrop| commands, and combine them into a single undo entry.

[yosin_UTC9, 2016/10/03 09:19:03]

Could you reflow a comment to fit in 80 chars / line style?

[chongz, 2016/10/04 02:18:39]

Done.

+// In the future when necessary, this mechanism can be generalized into a common command wrapper to achieve undo group.
+class DragAndDropCommand final : public CompositeEditCommand {
+public:
+    static DragAndDropCommand* create(Document& document)
+    {
+        return new DragAndDropCommand(document);
+    }
+
+    bool isCommandGroupWrapper() const override;
+    bool isDragAndDropCommand() const override;
+
+private:
+    explicit DragAndDropCommand(Document&);
+
+    void doApply(EditingState*) override;
+    InputEvent::InputType inputType() const override;
+};
+
+} // namespace blink
+
+#endif // DragAndDropCommand_h