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

core/src/fxcodec/codec/fx_codec_flate.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 "codec_int.h"
 #include "core/include/fxcodec/fx_codec.h"
 #include "core/include/fxcodec/fx_codec_flate.h"
 #include "third_party/base/nonstd_unique_ptr.h"
@@ skipping 16 matching lines @@
 }
 static void FPDFAPI_FlateCompress(unsigned char* dest_buf,
                                   unsigned long* dest_size,
                                   const unsigned char* src_buf,
                                   unsigned long src_size) {
   compress(dest_buf, dest_size, src_buf, src_size);
 }
 void* FPDFAPI_FlateInit(void* (*alloc_func)(void*, unsigned int, unsigned int),
                         void (*free_func)(void*, void*)) {
   z_stream* p = (z_stream*)alloc_func(0, 1, sizeof(z_stream));
-  if (p == NULL) {
+  if (!p) {
     return NULL;
   }
   FXSYS_memset(p, 0, sizeof(z_stream));
   p->zalloc = alloc_func;
   p->zfree = free_func;
   inflateInit(p);
   return p;
 }
 void FPDFAPI_FlateInput(void* context,
                         const unsigned char* src_buf,
@@ skipping 780 matching lines @@
       m_pPredictRaw = FX_Alloc(uint8_t, m_PredictPitch + 1);
       m_pPredictBuffer = FX_Alloc(uint8_t, m_PredictPitch);
     }
   }
 }
 FX_BOOL CCodec_FlateScanlineDecoder::v_Rewind() {
   if (m_pFlate) {
     FPDFAPI_FlateEnd(m_pFlate);
   }
   m_pFlate = FPDFAPI_FlateInit(my_alloc_func, my_free_func);
-  if (m_pFlate == NULL) {
+  if (!m_pFlate) {
     return FALSE;
   }
   FPDFAPI_FlateInput(m_pFlate, m_SrcBuf, m_SrcSize);
   m_LeftOver = 0;
   return TRUE;
 }
 uint8_t* CCodec_FlateScanlineDecoder::v_GetNextLine() {
   if (m_Predictor) {
     if (m_Pitch == m_PredictPitch) {
       if (m_Predictor == 2) {
@@ skipping 145 matching lines @@
                                    FX_DWORD src_size,
                                    uint8_t*& dest_buf,
                                    FX_DWORD& dest_size) {
   dest_size = src_size + src_size / 1000 + 12;
   dest_buf = FX_Alloc(uint8_t, dest_size);
   unsigned long temp_size = dest_size;
   FPDFAPI_FlateCompress(dest_buf, &temp_size, src_buf, src_size);
   dest_size = (FX_DWORD)temp_size;
   return TRUE;
 }