Fix a hang issue due to inconsistent page number in the test file

samples/pdfium_test.cc

 // Copyright (c) 2010 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 <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <list>
@@ skipping 286 matching lines @@
   (void) FPDFAvail_IsPageAvail(pdf_avail, first_page, &hints);
 
   int page_count = FPDF_GetPageCount(doc);
   for (int i = 0; i < page_count; ++i) {
     (void) FPDFAvail_IsPageAvail(pdf_avail, i, &hints);
   }
 
   FORM_DoDocumentJSAction(form);
   FORM_DoDocumentOpenAction(form);
 
+  size_t rendered_pages = 0;
+  size_t bad_pages = 0;
   for (int i = 0; i < page_count; ++i) {
     FPDF_PAGE page = FPDF_LoadPage(doc, i);
+    if (!page) {
+        bad_pages ++;
+        continue;
+    }
     FPDF_TEXTPAGE text_page = FPDFText_LoadPage(page);
     FORM_OnAfterLoadPage(page, form);
     FORM_DoPageAAction(page, form, FPDFPAGE_AACTION_OPEN);
 
     int width = static_cast<int>(FPDF_GetPageWidth(page));
     int height = static_cast<int>(FPDF_GetPageHeight(page));
     FPDF_BITMAP bitmap = FPDFBitmap_Create(width, height, 0);
     FPDFBitmap_FillRect(bitmap, 0, 0, width, height, 0xFFFFFFFF);
 
     FPDF_RenderPageBitmap(bitmap, page, 0, 0, width, height, 0, 0);
+    rendered_pages ++;
+
     FPDF_FFLDraw(form, bitmap, page, 0, 0, width, height, 0, 0);
     int stride = FPDFBitmap_GetStride(bitmap);
     const char* buffer =
         reinterpret_cast<const char*>(FPDFBitmap_GetBuffer(bitmap));
 
     switch (format) {
 #ifdef _WIN32
       case OUTPUT_BMP:
         WriteBmp(name, i, buffer, stride, width, height);
         break;
@@ skipping 15 matching lines @@
     FORM_OnBeforeClosePage(page, form);
     FPDFText_ClosePage(text_page);
     FPDF_ClosePage(page);
   }
 
   FORM_DoDocumentAAction(form, FPDFDOC_AACTION_WC);
   FPDFDOC_ExitFormFillEnviroument(form);
   FPDF_CloseDocument(doc);
   FPDFAvail_Destroy(pdf_avail);
 
-  printf("Loaded, parsed and rendered %d pages.\n", page_count);
+  printf("Loaded, parsed and rendered %d pages.\n", rendered_pages);
+  printf("Skipped %d bad pages.\n", bad_pages);
 }
 
 int main(int argc, const char* argv[]) {
   v8::V8::InitializeICU();
   OutputFormat format = OUTPUT_NONE;
   std::list<const char*> files;
   if (!ParseCommandLine(argc, argv, &format, &files)) {
     printf("Usage: pdfium_test [OPTION] [FILE]...\n");
     printf("--ppm    write page images <pdf-name>.<page-number>.ppm\n");
 #ifdef _WIN32
@@ skipping 31 matching lines @@
     } else {
       RenderPdf(filename, pBuf, len, format);
     }
     free(pBuf);
   }
 
   FPDF_DestroyLibrary();
 
   return 0;
 }