Use nullptr instead of 0 in call to FontConfig.

src/ports/SkFontConfigInterface_direct.cpp

 /*
  * Copyright 2009-2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* migrated from chrome/src/skia/ext/SkFontHost_fontconfig_direct.cpp */
 
 #include "SkBuffer.h"
@@ skipping 614 matching lines @@
     //
     // However, we special-case fallback fonts; see IsFallbackFontAllowed().
 
     const char* post_config_family = get_name(pattern, FC_FAMILY);
     if (!post_config_family) {
         // we can just continue with an empty name, e.g. default font
         post_config_family = "";
     }
 
     FcResult result;
-    FcFontSet* font_set = FcFontSort(0, pattern, 0, 0, &result);
+    FcFontSet* font_set = FcFontSort(nullptr, pattern, 0, nullptr, &result);
     if (!font_set) {
         FcPatternDestroy(pattern);
         return false;
     }
 
     FcPattern* match = this->MatchFont(font_set, post_config_family, familyStr);
     if (!match) {
         FcPatternDestroy(pattern);
         FcFontSetDestroy(font_set);
         return false;
@@ skipping 80 matching lines @@
         const char* famName = get_name(match, FC_FAMILY);
         if (famName && !find_name(names, famName)) {
             *names.append() = famName;
             *sizes.append() = strlen(famName) + 1;
         }
     }
 
     return SkDataTable::NewCopyArrays((const void*const*)names.begin(),
                                       sizes.begin(), names.count());
 }