Call FPDFAvail_IsFormAvail() before creating form.

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 0528c94ecca007a1e58ec053c96689974027318d..f9f2877f0a825ba95c2d9cc5493e71ec8a1e434b 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -2598,9 +2598,10 @@ void PDFiumEngine::ContinueLoadingDocument(
 
   if (!form_) {
     // Only returns 0 when data isn't available.  If form data is downloaded, or
-    // if this isn't a form, returns positive values.
-    if (!doc_loader_.IsDocumentComplete() &&
-        !FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_)) {
+    // if this isn't a form, returns positive values. FPDFAvail_IsFormAvail()
+    // must be called before continuing, so it must come first in the condition.
+    if (!FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_) &&

[Lei Zhang, 2015/12/30 01:09:21]

How about we call these 2 functions separately, and then compare their results?
It's probably better to do more checking for FPDFAvail_IsFormAvail() since it's
not returning a bool. I think you'd want to make sure it returned
PDF_FORM_AVAIL.

[spelchat, 2015/12/30 17:14:58]

PDF_FORM_NOTEXIST is OK too, it just means there is no form in the PDF.
PDF_FORM_ERROR shouldn't happen.

I've massaged the code a bit to make things clearer, !FPDFAvail_IsFormAvail()
was confusing.

+        !doc_loader_.IsDocumentComplete()) {
       return;
     }