Remove "this==NULL" and adjust corresponding callers

core/src/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 "../../../include/fpdfapi/fpdf_serial.h"
 #include "editint.h"
 #define PDF_OBJECTSTREAM_MAXLENGTH      (256 * 1024)
 #define PDF_XREFSTREAM_MAXSIZE          10000
@@ skipping 316 matching lines @@
 void CPDF_FlateEncoder::CloneDict()
 {
     if (!m_bCloned) {
         m_pDict = (CPDF_Dictionary*)m_pDict->Clone();
         m_bCloned = TRUE;
     }
 }
 FX_BOOL CPDF_FlateEncoder::Initialize(CPDF_Stream* pStream, FX_BOOL bFlateEncode)
 {
     m_Acc.LoadAllData(pStream, TRUE);
-    if (pStream->GetDict()->KeyExist("Filter") || !bFlateEncode) {
+    if ((pStream && pStream->GetDict() && pStream->GetDict()->KeyExist("Filter")) || !bFlateEncode) {
         if (pStream->GetDict()->KeyExist("Filter") && !bFlateEncode) {
             CPDF_StreamAcc destAcc;
             destAcc.LoadAllData(pStream);
             m_dwSize = destAcc.GetSize();
             m_pData = (FX_LPBYTE)destAcc.DetachData();
             m_pDict = (CPDF_Dictionary*)pStream->GetDict()->Clone();
             m_pDict->RemoveAt(FX_BSTRC("Filter"));
             m_bNewData = TRUE;
             m_bCloned = TRUE;
         } else {
@@ skipping 1127 matching lines @@
 FX_INT32 CPDF_Creator::WriteDoc_Stage1(IFX_Pause *pPause)
 {
     FXSYS_assert(m_iStage > -1 || m_iStage < 20);
     if (m_iStage == 0) {
         if (m_pParser == NULL) {
             m_dwFlags &= ~FPDFCREATE_INCREMENTAL;
         }
         if (m_bSecurityChanged && (m_dwFlags & FPDFCREATE_NO_ORIGINAL) == 0) {
             m_dwFlags &= ~FPDFCREATE_INCREMENTAL;
         }
-        m_pMetadata = m_pDocument->GetRoot()->GetElementValue(FX_BSTRC("Metadata"));
+        CPDF_Dictionary* pDict = m_pDocument->GetRoot();
+        m_pMetadata = pDict ? pDict->GetElementValue(FX_BSTRC("Metadata")) : NULL;
         if (m_dwFlags & FPDFCREATE_OBJECTSTREAM) {
             m_pXRefStream = FX_NEW CPDF_XRefStream;
             m_pXRefStream->Start();
             if ((m_dwFlags & FPDFCREATE_INCREMENTAL) != 0 && m_pParser) {
                 FX_FILESIZE prev = m_pParser->GetLastXRefOffset();
                 m_pXRefStream->m_PrevOffset = prev;
             }
         }
         m_iStage = 10;
     }
@@ skipping 529 matching lines @@
     }
     return Continue(NULL) > -1;
 }
 void CPDF_Creator::InitID(FX_BOOL bDefault )
 {
     CPDF_Array* pOldIDArray = m_pParser ? m_pParser->GetIDArray() : NULL;
     FX_BOOL bNewId = !m_pIDArray;
     if (!m_pIDArray) {
         FX_LPDWORD pBuffer = NULL;
         m_pIDArray = CPDF_Array::Create();
-        CPDF_Object* pID1 = pOldIDArray->GetElement(0);
+        CPDF_Object* pID1 = pOldIDArray ? pOldIDArray->GetElement(0) : NULL;
         if (pID1) {
             m_pIDArray->Add(pID1->Clone());
         } else {
             pBuffer = FX_Alloc(FX_DWORD, 4);
             PDF_GenerateFileID((FX_DWORD)(FX_UINTPTR)this, m_dwLastObjNum, pBuffer);
             CFX_ByteStringC bsBuffer((FX_LPCBYTE)pBuffer, 4 * sizeof(FX_DWORD));
             m_pIDArray->Add(CPDF_String::Create(bsBuffer, TRUE), m_pDocument);
         }
         if (pBuffer) {
             FX_Free(pBuffer);
@@ skipping 83 matching lines @@
     m_bNewCrypto = FALSE;
     if (!m_bStandardSecurity) {
         return;
     }
     if (m_pEncryptDict) {
         m_pEncryptDict->Release();
         m_pEncryptDict = NULL;
     }
     m_bStandardSecurity = FALSE;
 }