Code change to avoid signed/unsigned mismatch warnings

core/fpdfapi/fpdf_edit/fpdf_edit_create.cpp

 // Copyright 2014 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
 
 #include "core/fpdfapi/fpdf_edit/editint.h"
 
 #include <vector>
 
@@ skipping 1392 matching lines @@
     m_ObjectOffset.Add(dwStart, j - dwStart);
     dwStart = j;
   }
 }
 void CPDF_Creator::InitNewObjNumOffsets() {
   FX_BOOL bIncremental = (m_dwFlags & FPDFCREATE_INCREMENTAL) != 0;
   FX_BOOL bNoOriginal = (m_dwFlags & FPDFCREATE_NO_ORIGINAL) != 0;
   for (const auto& pair : m_pDocument->m_IndirectObjs) {
     const uint32_t objnum = pair.first;
     const CPDF_Object* pObj = pair.second;
-    if (pObj->GetObjNum() == -1)
+    if (pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
       continue;
     if (bIncremental) {
       if (!pObj->IsModified())
         continue;
     } else if (m_pParser && m_pParser->IsValidObjectNumber(objnum) &&
                m_pParser->GetObjectType(objnum)) {
       continue;
     }
     AppendNewObjNum(objnum);
   }
@@ skipping 645 matching lines @@
   m_bNewCrypto = FALSE;
   if (!m_bStandardSecurity) {
     return;
   }
   if (m_pEncryptDict) {
     m_pEncryptDict->Release();
     m_pEncryptDict = NULL;
   }
   m_bStandardSecurity = FALSE;
 }