Resolve macro redefinition warnings when built in Chromium

third_party/third_party.gyp

 # 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.
 
 {
   'variables': {
     'pdf_enable_xfa%': 0,  # Set to 1 by standalone.gypi in standalone builds.
     'pdf_use_skia%': 0,
   },
   'target_defaults': {
     'defines': [
       'OPJ_STATIC',
       'PNG_PREFIX',
       'PNG_USE_READ_MACROS',
-      '_CRT_SECURE_NO_WARNINGS',
     ],
     'include_dirs': [
       # This is implicit in GN.
       '<(DEPTH)',
       '..',
     ],
     'msvs_disabled_warnings': [
-      4005, 4018, 4146, 4333, 4345, 4267
+      4018, 4146, 4333, 4345, 4267
     ],
   },
   'targets': [
     {
       'target_name': 'bigint',
       'type': 'static_library',
       'sources': [
         'bigint/BigInteger.hh',
         'bigint/BigIntegerLibrary.hh',
         'bigint/BigIntegerUtils.hh',
@@ skipping 370 matching lines @@
             'libtiff/tif_read.c',
             'libtiff/tif_strip.c',
             'libtiff/tif_swab.c',
             'libtiff/tif_thunder.c',
             'libtiff/tif_tile.c',
             'libtiff/tif_version.c',
             'libtiff/tif_warning.c',
             'libtiff/tif_write.c',
             'libtiff/tif_zip.c',
           ],
+          'conditions': [
+            ['OS=="win"', {
+              'defines!': [
+                 # Need to undefine the macro since it is redefined in
+                 # tif_ojpeg.c and tif_jpeg.c.
+                'WIN32_LEAN_AND_MEAN',
+              ],
+            }],
+          ],
         },
       ],
     }],
   ],
 }