Re-enable several MSVC warnings

core/fpdfdoc/doc_ap.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/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_document.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_simple_parser.h"
 #include "core/fpdfdoc/doc_utils.h"
@@ skipping 285 matching lines @@
   }
   FX_FLOAT fFontSize = FX_atof(syntax.GetWord());
   CPVT_Color crText = ParseColor(DA);
   FX_BOOL bUseFormRes = FALSE;
   CPDF_Dictionary* pFontDict = NULL;
   CPDF_Dictionary* pDRDict = pAnnotDict->GetDictBy("DR");
   if (!pDRDict) {
     pDRDict = pFormDict->GetDictBy("DR");
     bUseFormRes = TRUE;
   }
-  CPDF_Dictionary* pDRFontDict = NULL;
-  if (pDRDict && (pDRFontDict = pDRDict->GetDictBy("Font"))) {
+  CPDF_Dictionary* pDRFontDict = pDRDict ? pDRDict->GetDictBy("Font") : nullptr;
+  if (pDRFontDict) {
     pFontDict = pDRFontDict->GetDictBy(sFontName.Mid(1));
     if (!pFontDict && !bUseFormRes) {
       pDRDict = pFormDict->GetDictBy("DR");
       pDRFontDict = pDRDict->GetDictBy("Font");
       if (pDRFontDict) {
         pFontDict = pDRFontDict->GetDictBy(sFontName.Mid(1));
       }
     }
   }
   if (!pDRFontDict) {
@@ skipping 609 matching lines @@
     case CPVT_Color::kCMYK:
       sColorStream << color.fColor1 << " " << color.fColor2 << " "
                    << color.fColor3 << " " << color.fColor4 << " "
                    << (bFillOrStroke ? "k" : "K") << "\n";
       break;
     case CPVT_Color::kTransparent:
       break;
   }
   return sColorStream.GetByteString();
 }