Use string pools in some dictionaries

core/fpdfdoc/include/cpdf_filespec.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_FPDFDOC_INCLUDE_CPDF_FILESPEC_H_
 #define CORE_FPDFDOC_INCLUDE_CPDF_FILESPEC_H_
 
+#include "core/fxcrt/include/cfx_string_pool_template.h"
+#include "core/fxcrt/include/cfx_weak_ptr.h"
 #include "core/fxcrt/include/fx_string.h"
 
 class CPDF_Object;
 
 class CPDF_FileSpec {
  public:
-  CPDF_FileSpec();
+  explicit CPDF_FileSpec(const CFX_WeakPtr<CFX_ByteStringPool>& pPool);
   explicit CPDF_FileSpec(CPDF_Object* pObj) : m_pObj(pObj) {}
 
   // Convert a platform dependent file name into pdf format.
   static CFX_WideString EncodeFileName(const CFX_WideStringC& filepath);
 
   // Convert a pdf file name into platform dependent format.
   static CFX_WideString DecodeFileName(const CFX_WideStringC& filepath);
 
   CPDF_Object* GetObj() const { return m_pObj; }
   bool GetFileName(CFX_WideString* wsFileName) const;
 
   // Set this file spec to refer to a file name (not a url).
   void SetFileName(const CFX_WideStringC& wsFileName);
 
  private:
   CPDF_Object* m_pObj;
 };
 
 #endif  // CORE_FPDFDOC_INCLUDE_CPDF_FILESPEC_H_