Fix a bunch of sign mismatch warnings.

core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp

Index: core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
diff --git a/core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp b/core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
index 8b0bff025761d6ef2a54b91c179c2708b629c4ed..252a4d6e4fef7946baed84af6d7b804284db97db 100644
--- a/core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
+++ b/core/src/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
@@ -8,6 +8,7 @@
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../fpdf_font/font_int.h"
 #include "cmap_int.h"
+
 void FPDFAPI_FindEmbeddedCMap(const char* name,
                               int charset,
                               int coding,
@@ -179,7 +180,8 @@ FX_DWORD FPDFAPI_CharCodeFromCID(const FXCMAP_CMap* pMap, FX_WORD cid) {
   }
   return 0;
 }
-void FPDFAPI_LoadCID2UnicodeMap(int charset,
+
+void FPDFAPI_LoadCID2UnicodeMap(CIDSet charset,
                                 const FX_WORD*& pMap,
                                 FX_DWORD& count) {
   CPDF_FontGlobals* pFontGlobals =