Add SetCharacterDataCommand

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

+// Copyright 2017 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 SetCharacterDataCommand_h
+#define SetCharacterDataCommand_h
+
+#include "core/editing/commands/EditCommand.h"
+
+namespace blink {
+
+class CORE_EXPORT SetCharacterDataCommand final : public SimpleEditCommand {
+ public:
+  static SetCharacterDataCommand* create(Text* node,
+                                         unsigned offset,
+                                         unsigned count,
+                                         const String& text) {
+    return new SetCharacterDataCommand(node, offset, count, text);
+  }
+
+  // EditCommand implementation
+  void doUnapply() final;

[Xiaocheng, 2017/02/21 23:37:32]

Hiding doUnapply() as private ensures that only virtual calls via
SimpleEditCommand are allowed. In the unit test, the command should be stored as
a |SimpleEditCommand*| so that doUnapply() can be called.

+
+  DECLARE_VIRTUAL_TRACE();
+
+ private:
+  SetCharacterDataCommand(Text* node,
+                          unsigned offset,
+                          unsigned count,
+                          const String& text);
+
+  // EditCommand implementation
+  void doApply(EditingState*) final;
+
+  const Member<Text> m_node;
+  const unsigned m_offset;
+  const unsigned m_count;
+  String m_previousTextForUndo;
+  const String m_newText;
+};
+
+}  // namespace blink
+
+#endif  // SetCharacterDataCommand_h