Use file handles to interact with utility process.

chrome/utility/printing_handler.h

 // Copyright 2014 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 CHROME_UTILITY_PRINTING_HANDLER_H_
 #define CHROME_UTILITY_PRINTING_HANDLER_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "chrome/utility/utility_message_handler.h"
 #include "ipc/ipc_platform_file.h"
+#include "printing/pdf_render_settings.h"
 
 #if !defined(ENABLE_FULL_PRINTING) && !defined(OS_WIN)
 #error "Windows or full printing must be enabled"
 #endif
 
 namespace printing {
 class PdfRenderSettings;
 struct PwgRasterSettings;
 struct PageRange;
 }
 
 // Dispatches IPCs for printing.
 class PrintingHandler : public UtilityMessageHandler {
  public:
   PrintingHandler();
   virtual ~PrintingHandler();
 
   static void PreSandboxStartup();
 
   // IPC::Listener:
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
  private:
   // IPC message handlers.
 #if defined(OS_WIN)
-  void OnRenderPDFPagesToMetafile(
-      IPC::PlatformFileForTransit pdf_transit,
-      const base::FilePath& metafile_path,
-      const printing::PdfRenderSettings& settings,
-      const std::vector<printing::PageRange>& page_ranges);
+  void OnRenderPDFPagesToMetafile(IPC::PlatformFileForTransit pdf_transit,
+                                  const printing::PdfRenderSettings& settings);
+  void OnRenderPDFPagesToMetafileGetPage(
+      int page_number,
+      IPC::PlatformFileForTransit output_file);
 #endif  // OS_WIN
 #if defined(ENABLE_FULL_PRINTING)
   void OnRenderPDFPagesToPWGRaster(
       IPC::PlatformFileForTransit pdf_transit,
       const printing::PdfRenderSettings& settings,
       const printing::PwgRasterSettings& bitmap_settings,
       IPC::PlatformFileForTransit bitmap_transit);
 #endif  // ENABLE_FULL_PRINTING
 
 #if defined(OS_WIN)
-  // Helper method for Windows.
-  // |highest_rendered_page_number| is set to -1 on failure to render any page.
-  // |page_ranges| is both input and output. If supplied as input, only the
-  // specified pages will be rendered. If an empty vector is supplied it will
-  // be filled with a range of all pages that were rendered.
-  bool RenderPDFToWinMetafile(
-      base::File pdf_file,
-      const base::FilePath& metafile_path,
-      const printing::PdfRenderSettings& settings,
-      std::vector<printing::PageRange>* page_ranges,
-      int* highest_rendered_page_number,
-      double* scale_factor);
+  int LoadPDF(base::File pdf_file);
+  bool RenderPdfPageToMetafile(int page_number,
+                               base::File output_file,
+                               double* scale_factor);
 #endif  // OS_WIN
 #if defined(ENABLE_FULL_PRINTING)
   bool RenderPDFPagesToPWGRaster(
       base::File pdf_file,
       const printing::PdfRenderSettings& settings,
       const printing::PwgRasterSettings& bitmap_settings,
       base::File bitmap_file);
 
   void OnGetPrinterCapsAndDefaults(const std::string& printer_name);
   void OnGetPrinterSemanticCapsAndDefaults(const std::string& printer_name);
 #endif  // ENABLE_FULL_PRINTING
 
+#if defined(OS_WIN)
+  std::vector<char> pdf_data_;
+  printing::PdfRenderSettings pdf_rendering_settings_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(PrintingHandler);
 };
 
 #endif  // CHROME_UTILITY_PRINTING_HANDLER_H_