Use FXFONT defines in place of integers.

core/fpdfdoc/cpvt_fontmap.cpp

Index: core/fpdfdoc/cpvt_fontmap.cpp
diff --git a/core/fpdfdoc/cpvt_fontmap.cpp b/core/fpdfdoc/cpvt_fontmap.cpp
index d4171bd1470ffef2d6922ef264cb57270d251454..35a56f811df8c93e55b69fd5e7b3499cd813e8fc 100644
--- a/core/fpdfdoc/cpvt_fontmap.cpp
+++ b/core/fpdfdoc/cpvt_fontmap.cpp
@@ -88,5 +88,5 @@ int32_t CPVT_FontMap::CharCodeFromUnicode(int32_t nFontIndex, uint16_t word) {
 
 int32_t CPVT_FontMap::CharSetFromUnicode(uint16_t word, int32_t nOldCharset) {
   ASSERT(false);
-  return 0;
+  return FXFONT_ANSI_CHARSET;
 }