Get rid of NULLs in core/

core/fxge/apple/fx_mac_imp.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/fxge/apple/apple_int.h"
 #include "core/fxge/include/fx_ge.h"
 
 #if _FX_OS_ == _FX_MACOSX_
@@ skipping 56 matching lines @@
     return GetFont(face.c_str());
   }
   auto it = m_FontList.find(face);
   if (it != m_FontList.end())
     return it->second;
 
   if (charset == FXFONT_ANSI_CHARSET && (pitch_family & FXFONT_FF_FIXEDPITCH)) {
     return GetFont("Courier New");
   }
   if (charset == FXFONT_ANSI_CHARSET || charset == FXFONT_SYMBOL_CHARSET) {
-    return NULL;
+    return nullptr;
   }
   switch (charset) {
     case FXFONT_SHIFTJIS_CHARSET:
       GetJapanesePreference(face, weight, pitch_family);
       break;
     case FXFONT_GB2312_CHARSET:
       face = "STSong";
       break;
     case FXFONT_HANGEUL_CHARSET:
       face = "AppleMyungjo";
       break;
     case FXFONT_CHINESEBIG5_CHARSET:
       face = "LiSong Pro Light";
   }
   it = m_FontList.find(face);
   if (it != m_FontList.end())
     return it->second;
 
-  return NULL;
+  return nullptr;
 }
 
 std::unique_ptr<IFX_SystemFontInfo> IFX_SystemFontInfo::CreateDefault(
     const char** pUnused) {
   CFX_MacFontInfo* pInfo(new CFX_MacFontInfo);
   pInfo->AddPath("~/Library/Fonts");
   pInfo->AddPath("/Library/Fonts");
   pInfo->AddPath("/System/Library/Fonts");
   return std::unique_ptr<CFX_MacFontInfo>(pInfo);
 }
 
 void CFX_GEModule::InitPlatform() {
   m_pPlatformData = new CApplePlatform;
   m_pFontMgr->SetSystemFontInfo(IFX_SystemFontInfo::CreateDefault(nullptr));
 }
 void CFX_GEModule::DestroyPlatform() {
   delete (CApplePlatform*)m_pPlatformData;
-  m_pPlatformData = NULL;
+  m_pPlatformData = nullptr;
 }
 #endif