Printing: Load the source PDF only once.

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 753 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(ScopedSubstFont);
 };
 
 class PDFiumEngineExports : public PDFEngineExports {
  public:
   PDFiumEngineExports() {}
 
 // PDFEngineExports:
 #if defined(OS_WIN)
-  bool RenderPDFPageToDC(const void* pdf_buffer,
-                         int buffer_size,
+  bool RenderPDFPageToDC(void* pdf_handle,
                          int page_number,
                          const RenderingSettings& settings,
                          HDC dc) override;
   void SetPDFEnsureTypefaceCharactersAccessible(
       PDFEnsureTypefaceCharactersAccessible func) override;
 
   void SetPDFUseGDIPrinting(bool enable) override;
 #endif  // defined(OS_WIN)
-  bool RenderPDFPageToBitmap(const void* pdf_buffer,
-                             int pdf_buffer_size,
+  bool RenderPDFPageToBitmap(void* pdf_handle,
                              int page_number,
                              const RenderingSettings& settings,
                              void* bitmap_buffer) override;
   bool GetPDFDocInfo(const void* pdf_buffer,
                      int buffer_size,
                      int* page_count,
-                     double* max_page_width) override;
-  bool GetPDFPageSizeByIndex(const void* pdf_buffer,
-                             int pdf_buffer_size,
+                     double* max_page_width,
+                     void** pdf_handle) override;
+  void ReleasePDFHandle(void* pdf_handle) override;
+  bool GetPDFPageSizeByIndex(void* pdf_handle,
                              int page_number,
                              double* width,
                              double* height) override;
 };
 
 }  // namespace chrome_pdf
 
 #endif  // PDF_PDFIUM_PDFIUM_ENGINE_H_