Convert loose FX_Create* functions into static methods

core/fpdfapi/parser/cfdf_document.cpp

Index: core/fpdfapi/parser/cfdf_document.cpp
diff --git a/core/fpdfapi/parser/cfdf_document.cpp b/core/fpdfapi/parser/cfdf_document.cpp
index 41e285245da2b86e07c020c09ef39c70e2d67bff..a6045e7795e37a359c18ee92a1bbcef57a43a933 100644
--- a/core/fpdfapi/parser/cfdf_document.cpp
+++ b/core/fpdfapi/parser/cfdf_document.cpp
@@ -45,8 +45,8 @@ std::unique_ptr<CFDF_Document> CFDF_Document::ParseFile(
 
 std::unique_ptr<CFDF_Document> CFDF_Document::ParseMemory(const uint8_t* pData,
                                                           uint32_t size) {
-  return CFDF_Document::ParseFile(FX_CreateMemoryStream((uint8_t*)pData, size),
-                                  true);
+  return CFDF_Document::ParseFile(
+      IFX_MemoryStream::Create((uint8_t*)pData, size), true);
 }
 
 void CFDF_Document::ParseStream(IFX_SeekableReadStream* pFile, bool bOwnFile) {