Fixup FPDFAvail_IsPageAvail checks in PDFiumEngine.

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1081 matching lines @@
   DCHECK(doc_loader_.IsDocumentComplete() && doc_);
 
   bool need_update = false;
   for (size_t i = 0; i < pages_.size(); ++i) {
     if (pages_[i]->available())
       continue;
 
     pages_[i]->set_available(true);
     // We still need to call IsPageAvail() even if the whole document is
     // already downloaded.
-    FPDFAvail_IsPageAvail(fpdf_availability_, i, &download_hints_);
+    while (true) {

[dsinclair, 2016/06/02 18:03:25]

This is probably bad, and I feel bad, but I wasn't sure the correct solution
....

+      int val = FPDFAvail_IsPageAvail(fpdf_availability_, i, &download_hints_);
+      if (val == PDF_DATA_ERROR)
+        return;
+      if (val == PDF_DATA_AVAIL)
+        break;
+    }
     need_update = true;
     if (IsPageVisible(i))
       client_->Invalidate(GetPageScreenRect(i));
   }
   if (need_update)
     LoadPageInfo(true);
 
   if (called_do_document_action_)
     return;
   called_do_document_action_ = true;
@@ skipping 1514 matching lines @@
 }
 
 bool PDFiumEngine::CheckPageAvailable(int index, std::vector<int>* pending) {
   if (!doc_ || !form_)
     return false;
 
   const int num_pages = static_cast<int>(pages_.size());
   if (index < num_pages && pages_[index]->available())
     return true;
 
-  if (!FPDFAvail_IsPageAvail(fpdf_availability_, index, &download_hints_)) {
+  if (FPDFAvail_IsPageAvail(fpdf_availability_, index, &download_hints_) !=
+      PDF_DATA_AVAIL) {
     if (!ContainsValue(*pending, index))
       pending->push_back(index);
     return false;
   }
 
   if (index < num_pages)
     pages_[index]->set_available(true);
   if (!default_page_size_.GetArea())
     default_page_size_ = GetPageSize(index);
   return true;
@@ skipping 1222 matching lines @@
   FPDF_DOCUMENT doc =
       FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, nullptr);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf