AddUndo
fUndoBuffer.AddUndo(item->RedoText, item->Length, item->Offset, item->History, item->CursorPos);
fUndoBuffer.AddUndo(undo->RedoText, undo->Length,
fInputMethodUndoBuffer.AddUndo(insertText, length, offset, K_INSERTED, cursorPos);
fUndoBuffer.AddUndo(insertText, length, offset, K_REPLACED, cursorPos);
fUndoBuffer.AddUndo(insertText, length, offset, K_INSERTED, cursorPos);
fUndoBuffer.AddUndo(&Text()[start], finish - start, start, K_DELETED, cursorPos);
fInputMethodUndoBuffer.AddUndo(&Text()[start], finish - start, start,
fUndoBuffer.AddUndo(&Text()[start], finish - start, start, K_DELETED, cursorPos);
fUndoBuffer.AddUndo(item->RedoText, item->Length, item->Offset,
status_t AddUndo(const char* redo_text, int32 length,