PDF: Always call FPDFAvail_IsDocAvail() when loading.

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 ac00af5c590d3827fb2493b4e615f44729fed331..bf0d042fe05671bdb735b6d992ff296db0b918eb 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -298,7 +298,7 @@ FPDF_SYSFONTINFO g_font_info = {
 };
 #endif  // defined(OS_LINUX)
 
-PDFiumEngine* g_engine_for_unsupported;
+PDFiumEngine* g_engine_for_unsupported = nullptr;
 
 void Unsupported_Handler(UNSUPPORT_INFO*, int type) {
   if (!g_engine_for_unsupported) {
@@ -2391,10 +2391,13 @@ void PDFiumEngine::AppendBlankPages(int num_pages) {
 void PDFiumEngine::LoadDocument() {
   // Check if the document is ready for loading. If it isn't just bail for now,
   // we will call LoadDocument() again later.
-  if (!doc_ && !doc_loader_.IsDocumentComplete() &&
-      !FPDFAvail_IsDocAvail(fpdf_availability_, &download_hints_)) {

[Wei Li, 2016/05/24 00:21:27]

Should these conditions be ORed instead?

[Lei Zhang, 2016/05/25 17:16:36]

No, we have to continue past this point to turn |doc_| non-NULL. If it's ORed,
then this if statement always evals to false. Basically it's "we are looking for
a reason to try to load the document" so only return early if no such reason
exists.

+  if (!doc_ && !doc_loader_.IsDocumentComplete())
+    return;
+
+ // Always call FPDFAvail_IsDocAvail() so PDFium initializes internal data
+ // structures.
+  if (!FPDFAvail_IsDocAvail(fpdf_availability_, &download_hints_))
     return;
-  }
 
   // If we're in the middle of getting a password, just return. We will retry
   // loading the document after we get the password anyway.