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

core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.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 "cmap_int.h"
 
 #include "core/include/fpdfapi/fpdf_module.h"
 #include "core/include/fpdfapi/fpdf_resource.h"
@@ skipping 87 matching lines @@
       }
       if (pMap->m_UseOffset == 0) {
         return 0;
       }
       pMap = pMap + pMap->m_UseOffset;
     }
     return 0;
   }
   FX_WORD code = (FX_WORD)charcode;
   while (1) {
-    if (pMap->m_pWordMap == NULL) {
+    if (!pMap->m_pWordMap) {
       return 0;
     }
     if (pMap->m_WordMapType == FXCMAP_CMap::Single) {
       FX_WORD* found = (FX_WORD*)FXSYS_bsearch(
           &code, pMap->m_pWordMap, pMap->m_WordCount, 4, compareWord);
       if (found) {
         return found[1];
       }
     } else if (pMap->m_WordMapType == FXCMAP_CMap::Range) {
       FX_WORD* found = (FX_WORD*)FXSYS_bsearch(
@@ skipping 64 matching lines @@
 }
 
 void FPDFAPI_LoadCID2UnicodeMap(CIDSet charset,
                                 const FX_WORD*& pMap,
                                 FX_DWORD& count) {
   CPDF_FontGlobals* pFontGlobals =
       CPDF_ModuleMgr::Get()->GetPageModule()->GetFontGlobals();
   pMap = pFontGlobals->m_EmbeddedToUnicodes[charset].m_pMap;
   count = pFontGlobals->m_EmbeddedToUnicodes[charset].m_Count;
 }