Remove FX_DWORD from core/ and delete definition

core/fpdfapi/fpdf_parser/include/cpdf_reference.h

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_REFERENCE_H_
 #define CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_REFERENCE_H_
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_object.h"
@@ skipping 13 matching lines @@
   FX_FLOAT GetNumber() const override;
   int GetInteger() const override;
   CPDF_Dictionary* GetDict() const override;
 
   // TODO(weili): check whether GetUnicodeText() and GetArray() are needed.
   bool IsReference() const override;
   CPDF_Reference* AsReference() override;
   const CPDF_Reference* AsReference() const override;
 
   CPDF_IndirectObjectHolder* GetObjList() const { return m_pObjList; }
-  FX_DWORD GetRefObjNum() const { return m_RefObjNum; }
+  uint32_t GetRefObjNum() const { return m_RefObjNum; }
 
-  void SetRef(CPDF_IndirectObjectHolder* pDoc, FX_DWORD objnum);
+  void SetRef(CPDF_IndirectObjectHolder* pDoc, uint32_t objnum);
 
  protected:
   ~CPDF_Reference() override;
   CPDF_Object* SafeGetDirect() const {
     CPDF_Object* obj = GetDirect();
     if (!obj || obj->IsReference())
       return nullptr;
     return obj;
   }
 
   CPDF_IndirectObjectHolder* m_pObjList;
-  FX_DWORD m_RefObjNum;
+  uint32_t m_RefObjNum;
 };
 
 #endif  // CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_REFERENCE_H_