Get rid of most instance of 'foo == NULL'

core/src/fpdfapi/fpdf_edit/fpdf_edit_image.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/include/fpdfapi/fpdf_module.h"
 #include "core/include/fpdfapi/fpdf_page.h"
 #include "core/include/fpdfapi/fpdf_render.h"
 #include "core/include/fxcodec/fx_codec.h"
@@ skipping 33 matching lines @@
   pDict->SetAtInteger("BitsPerComponent", bits);
   pDict->SetAtName("Filter", "DCTDecode");
   if (!color_trans) {
     CPDF_Dictionary* pParms = new CPDF_Dictionary;
     pDict->SetAt("DecodeParms", pParms);
     pParms->SetAtInteger("ColorTransform", 0);
   }
   m_bIsMask = FALSE;
   m_Width = width;
   m_Height = height;
-  if (m_pStream == NULL) {
+  if (!m_pStream) {
     m_pStream = new CPDF_Stream(NULL, 0, NULL);
   }
   return pDict;
 }
 void CPDF_Image::SetJpegImage(uint8_t* pData, FX_DWORD size) {
   CPDF_Dictionary* pDict = InitJPEG(pData, size);
   if (!pDict) {
     return;
   }
   m_pStream->InitStream(pData, size, pDict);
@@ skipping 295 matching lines @@
       } else {
         pDest += dest_pitch;
       }
       dest_offset = 0;
     }
     if (bStream) {
       FX_Free(dest_buf);
       dest_buf = NULL;
     }
   }
-  if (m_pStream == NULL) {
+  if (!m_pStream) {
     m_pStream = new CPDF_Stream(NULL, 0, NULL);
   }
   if (!bStream) {
     m_pStream->InitStream(dest_buf, dest_size, pDict);
   } else {
     pFileWrite->Flush();
     m_pStream->InitStreamFromFile(pFileRead, pDict);
   }
   m_bIsMask = pBitmap->IsAlphaMask();
   m_Width = BitmapWidth;
   m_Height = BitmapHeight;
   FX_Free(dest_buf);
 }
 void CPDF_Image::ResetCache(CPDF_Page* pPage, const CFX_DIBitmap* pBitmap) {
   pPage->GetRenderCache()->ResetBitmap(m_pStream, pBitmap);
 }