Use std::map as CPDF_Dictionary's underlying store.

fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp

Index: fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
diff --git a/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp b/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
index 1649eaf35d38c1a1e0067b07eb154c70f39f5a70..9253563c3897640465588b6913c24283e82ce4ca 100644
--- a/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
+++ b/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
@@ -118,11 +118,9 @@ CPDF_Font* CBA_FontMap::FindResFontSameCharset(CPDF_Dictionary* pResDict,
 
   CPDF_Font* pFind = NULL;
 
-  FX_POSITION pos = pFonts->GetStartPos();
-  while (pos) {
-    CPDF_Object* pObj = NULL;
-    CFX_ByteString csKey;
-    pObj = pFonts->GetNextElement(pos, csKey);
+  for (const auto& it : *pFonts) {
+    const CFX_ByteString& csKey = it.first;
+    CPDF_Object* pObj = it.second;
     if (!pObj)
       continue;