Introduce InsertIncrementalTextCommand to respect existing style for composition

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

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef InsertTextCommand_h
 #define InsertTextCommand_h
 
 #include "core/editing/commands/CompositeEditCommand.h"
 
 namespace blink {
 
-class InsertTextCommand final : public CompositeEditCommand {
+class InsertTextCommand : public CompositeEditCommand {
  public:
   enum RebalanceType {
     RebalanceLeadingAndTrailingWhitespaces,
     RebalanceAllWhitespaces
   };
 
   static InsertTextCommand* create(
       Document& document,
       const String& text,
       bool selectInsertedText = false,
       RebalanceType rebalanceType = RebalanceLeadingAndTrailingWhitespaces) {
     return new InsertTextCommand(document, text, selectInsertedText,
                                  rebalanceType);
   }
 
   String textDataForInputEvent() const final;
 
- private:
+ protected:
   InsertTextCommand(Document&,
                     const String& text,
                     bool selectInsertedText,
                     RebalanceType);
 
   void doApply(EditingState*) override;
 
   Position positionInsideTextNode(const Position&, EditingState*);
   Position insertTab(const Position&, EditingState*);
 
   bool performTrivialReplace(const String&, bool selectInsertedText);
   bool performOverwrite(const String&, bool selectInsertedText);
   void setEndingSelectionWithoutValidation(const Position& startPosition,
                                            const Position& endPosition);
 
   friend class TypingCommand;
 
   String m_text;
   bool m_selectInsertedText;
   RebalanceType m_rebalanceType;
 };
 
 }  // namespace blink
 
 #endif  // InsertTextCommand_h