Validate page index in PDFiumEngine::ScrollToPage().

pdf/pdfium/pdfium_engine.h

 // 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.
 
 #ifndef PDF_PDFIUM_PDFIUM_ENGINE_H_
 #define PDF_PDFIUM_PDFIUM_ENGINE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 421 matching lines @@
 
   // Called when the selection changes.
   void OnSelectionChanged();
 
   // Common code shared by RotateClockwise() and RotateCounterclockwise().
   void RotateInternal();
 
   // Setting selection status of document.
   void SetSelecting(bool selecting);
 
+  bool PageIndexInBounds(int index) const;
+
   // FPDF_FORMFILLINFO callbacks.
   static void Form_Invalidate(FPDF_FORMFILLINFO* param,
                               FPDF_PAGE page,
                               double left,
                               double top,
                               double right,
                               double bottom);
   static void Form_OutputSelectedRect(FPDF_FORMFILLINFO* param,
                                       FPDF_PAGE page,
                                       double left,
@@ skipping 336 matching lines @@
   bool GetPDFPageSizeByIndex(const void* pdf_buffer,
                              int pdf_buffer_size,
                              int page_number,
                              double* width,
                              double* height) override;
 };
 
 }  // namespace chrome_pdf
 
 #endif  // PDF_PDFIUM_PDFIUM_ENGINE_H_