Rename DLLEXPORT AND STDCALL

This CL renames DLLEXPORT to FPDF_EXPORT and STDCALL to FPDF_CALLCONV to
be more PDFium specific.

This is split off of https://pdfium-review.googlesource.com/c/8970 by
Felix Kauselmann.

Bug: pdfium:825
Change-Id: I0aea9d43f1714b1e10e935c4a7eea685a5ad8998
Reviewed-on: https://pdfium-review.googlesource.com/10610
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/fpdfppo.cpp b/fpdfsdk/fpdfppo.cpp
index bf52932..905d53a 100644
--- a/fpdfsdk/fpdfppo.cpp
+++ b/fpdfsdk/fpdfppo.cpp
@@ -344,10 +344,10 @@
   return dwNewObjNum;
 }
 
-DLLEXPORT FPDF_BOOL STDCALL FPDF_ImportPages(FPDF_DOCUMENT dest_doc,
-                                             FPDF_DOCUMENT src_doc,
-                                             FPDF_BYTESTRING pagerange,
-                                             int index) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDF_ImportPages(FPDF_DOCUMENT dest_doc,
+                                                     FPDF_DOCUMENT src_doc,
+                                                     FPDF_BYTESTRING pagerange,
+                                                     int index) {
   CPDF_Document* pDestDoc = CPDFDocumentFromFPDFDocument(dest_doc);
   if (!dest_doc)
     return false;
@@ -371,8 +371,8 @@
   return pageOrg.PDFDocInit() && pageOrg.ExportPage(pageArray, index);
 }
 
-DLLEXPORT FPDF_BOOL STDCALL FPDF_CopyViewerPreferences(FPDF_DOCUMENT dest_doc,
-                                                       FPDF_DOCUMENT src_doc) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
+FPDF_CopyViewerPreferences(FPDF_DOCUMENT dest_doc, FPDF_DOCUMENT src_doc) {
   CPDF_Document* pDstDoc = CPDFDocumentFromFPDFDocument(dest_doc);
   if (!pDstDoc)
     return false;