Applying factory pattern (through NativeMetafileFactory class). It is used to retrieve different printing contexts (based on the platform and user preferences).

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/6544028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@76553 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 473 insertions, 121 deletions

diff --git a/printing/emf_win.h b/printing/emf_win.h
index f8a0558..ba139d8 100644
--- a/printing/emf_win.h
+++ b/printing/emf_win.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -9,6 +9,8 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
+#include "printing/native_metafile_win.h"
 
 class FilePath;
 
@@ -19,30 +21,31 @@ class Rect;
 namespace printing {
 
 // Simple wrapper class that manage an EMF data stream and its virtual HDC.
-class Emf {
+class Emf : public NativeMetafile {
  public:
   class Record;
   class Enumerator;
   struct EnumerationContext;
 
-  Emf();
-  ~Emf();
+  virtual ~Emf();
 
   // Initializes the Emf with the data in |src_buffer|. Returns true on success.
-  bool Init(const void* src_buffer, uint32 src_buffer_size);
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size);
 
   // Generates a virtual HDC that will record every GDI commands and compile it
   // in a EMF data stream.
   // hdc is used to setup the default DPI and color settings. hdc is optional.
   // rect specifies the dimensions (in .01-millimeter units) of the EMF. rect is
   // optional.
-  bool CreateDc(HDC sibling, const RECT* rect);
+  virtual bool CreateDc(HDC sibling, const RECT* rect);
 
   // Similar to the above method but the metafile is backed by a file.
-  bool CreateFileBackedDc(HDC sibling, const RECT* rect, const FilePath& path);
+  virtual bool CreateFileBackedDc(HDC sibling,
+                                  const RECT* rect,
+                                  const FilePath& path);
 
     // Load an EMF file.
-  bool CreateFromFile(const FilePath& metafile_path);
+  virtual bool CreateFromFile(const FilePath& metafile_path);
 
   // TODO(maruel): CreateFromFile(). If ever used. Maybe users would like to
   // have the ability to save web pages to an EMF file? Afterward, it is easy to
@@ -50,10 +53,10 @@ class Emf {
 
   // Closes the HDC created by CreateDc() and generates the compiled EMF
   // data.
-  bool CloseDc();
+  virtual bool CloseDc();
 
   // Closes the EMF data handle when it is not needed anymore.
-  void CloseEmf();
+  virtual void CloseEmf();
 
   // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
   // original GDI function that were called when recording the EMF. |rect| is in
@@ -63,47 +66,56 @@ class Emf {
   // functions, whether used directly or indirectly through precompiled EMF
   // data. We have to accept the risk here. Since it is used only for printing,
   // it requires user intervention.
-  bool Playback(HDC hdc, const RECT* rect) const;
+  virtual bool Playback(HDC hdc, const RECT* rect) const;
 
   // The slow version of Playback(). It enumerates all the records and play them
   // back in the HDC. The trick is that it skip over the records known to have
   // issue with some printers. See Emf::Record::SafePlayback implementation for
   // details.
-  bool SafePlayback(HDC hdc) const;
+  virtual bool SafePlayback(HDC hdc) const;
 
   // Retrieves the bounds of the painted area by this EMF buffer. This value
   // should be passed to Playback to keep the exact same size.
-  gfx::Rect GetBounds() const;
+  virtual gfx::Rect GetBounds() const;
 
   // Retrieves the EMF stream size.
-  uint32 GetDataSize() const;
+  virtual uint32 GetDataSize() const;
 
   // Retrieves the EMF stream.
-  bool GetData(void* buffer, uint32 size) const;
+  virtual bool GetData(void* buffer, uint32 size) const;
 
   // Retrieves the EMF stream. It is an helper function.
-  bool GetData(std::vector<uint8>* buffer) const;
+  virtual bool GetData(std::vector<uint8>* buffer) const;
 
-  HENHMETAFILE emf() const {
+  virtual HENHMETAFILE emf() const {
     return emf_;
   }
 
-  HDC hdc() const {
+  virtual HDC hdc() const {
     return hdc_;
   }
 
   // Inserts a custom GDICOMMENT records indicating StartPage/EndPage calls
   // (since StartPage and EndPage do not work in a metafile DC). Only valid
   // when hdc_ is non-NULL.
-  bool StartPage();
-  bool EndPage();
+  virtual bool StartPage();
+  virtual bool EndPage();
 
   // Saves the EMF data to a file as-is. It is recommended to use the .emf file
   // extension but it is not enforced. This function synchronously writes to the
   // file. For testing only.
-  bool SaveTo(const std::wstring& filename) const;
+  virtual bool SaveTo(const std::wstring& filename) const;
+
+ protected:
+  Emf();
 
  private:
+  friend class NativeMetafileFactory;
+  FRIEND_TEST_ALL_PREFIXES(EmfTest, DC);
+  FRIEND_TEST_ALL_PREFIXES(EmfTest, FileBackedDC);
+  FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
+  FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, PageBreak);
+
   // Playbacks safely one EMF record.
   static int CALLBACK SafePlaybackProc(HDC hdc,
                                        HANDLETABLE* handle_table,
diff --git a/printing/emf_win_unittest.cc b/printing/emf_win_unittest.cc
index 4312b2c..9d3aa00 100644..100755
--- a/printing/emf_win_unittest.cc
+++ b/printing/emf_win_unittest.cc
@@ -39,6 +39,8 @@ const uint32 EMF_HEADER_SIZE = 128;
 
 }  // namespace
 
+namespace printing {
+
 TEST(EmfTest, DC) {
   // Simplest use case.
   printing::Emf emf;
@@ -195,3 +197,4 @@ TEST(EmfTest, FileBackedDC) {
   emf.CloseEmf();
 }
 
+}  // namespace printing
diff --git a/printing/image.cc b/printing/image.cc
index 1116f32..a99e307 100644
--- a/printing/image.cc
+++ b/printing/image.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -6,7 +6,9 @@
 
 #include "base/file_util.h"
 #include "base/md5.h"
+#include "base/scoped_ptr.h"
 #include "base/string_number_conversions.h"
+#include "printing/native_metafile_factory.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/codec/png_codec.h"
 
@@ -144,9 +146,10 @@ bool Image::LoadPng(const std::string& compressed) {
 
 bool Image::LoadMetafile(const std::string& data) {
   DCHECK(!data.empty());
-  NativeMetafile metafile;
-  metafile.Init(data.data(), data.size());
-  return LoadMetafile(metafile);
+  scoped_ptr<NativeMetafile> metafile(
+      printing::NativeMetafileFactory::CreateMetafile());
+  metafile->Init(data.data(), data.size());
+  return LoadMetafile(*metafile);
 }
 
 }  // namespace printing
diff --git a/printing/native_metafile.h b/printing/native_metafile.h
index b0f957a..7e1d25b 100644
--- a/printing/native_metafile.h
+++ b/printing/native_metafile.h
@@ -1,50 +1,19 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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 PRINTING_NATIVE_METAFILE_H_
 #define PRINTING_NATIVE_METAFILE_H_
 
+#include "base/basictypes.h"
 #include "build/build_config.h"
 
-// Define a metafile format for the current platform.  We use this platform
-// independent define so we can define interfaces in platform agnostic manner.
-// It is still an outstanding design issue whether we create classes on all
-// platforms that have the same interface as Emf or if we change Emf to support
-// multiple platforms (and rename to NativeMetafile).
-
-
 #if defined(OS_WIN)
-
-#include "printing/emf_win.h"
-
-namespace printing {
-
-typedef Emf NativeMetafile;
-
-}  // namespace printing
-
+#include "printing/native_metafile_win.h"
 #elif defined(OS_MACOSX)
-
-#include "printing/pdf_metafile_mac.h"
-
-namespace printing {
-
-typedef PdfMetafile NativeMetafile;
-
-}  // namespace printing
-
+#include "printing/native_metafile_mac.h"
 #elif defined(OS_POSIX)
-
-#include "printing/pdf_ps_metafile_cairo.h"
-
-namespace printing {
-
-typedef PdfPsMetafile NativeMetafile;
-
-}  // namespace printing
-
+#include "printing/native_metafile_linux.h"
 #endif
 
-
 #endif  // PRINTING_NATIVE_METAFILE_H_
diff --git a/printing/native_metafile_factory.cc b/printing/native_metafile_factory.cc
new file mode 100644
index 0000000..a41428f
--- /dev/null
+++ b/printing/native_metafile_factory.cc
@@ -0,0 +1,28 @@
+// Copyright (c) 2011 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 "printing/native_metafile_factory.h"
+
+#if defined(OS_WIN)
+#include "printing/emf_win.h"
+#elif defined(OS_MACOSX)
+#include "printing/pdf_metafile_mac.h"
+#elif defined(OS_POSIX)
+#include "printing/pdf_ps_metafile_cairo.h"
+#endif
+
+namespace printing {
+
+// static
+printing::NativeMetafile* NativeMetafileFactory::CreateMetafile() {
+#if defined(OS_WIN)
+  return new printing::Emf;
+#elif defined(OS_MACOSX)
+  return new printing::PdfMetafile;
+#elif defined(OS_POSIX)
+  return new printing::PdfPsMetafile;
+#endif
+}
+
+}  // namespace printing
diff --git a/printing/native_metafile_factory.h b/printing/native_metafile_factory.h
new file mode 100644
index 0000000..d1543c7
--- /dev/null
+++ b/printing/native_metafile_factory.h
@@ -0,0 +1,30 @@
+// Copyright (c) 2011 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 PRINTING_NATIVE_METAFILE_FACTORY_H_
+#define PRINTING_NATIVE_METAFILE_FACTORY_H_
+
+#include "base/basictypes.h"
+#include "printing/native_metafile.h"
+
+namespace printing {
+
+// Various printing contexts will be supported in the future (cairo, skia, emf).
+// So this class returns the appropriate context depending on the platform and
+// user preferences.
+// (Note: For the moment there is only one option per platform.)
+class NativeMetafileFactory {
+ public:
+  // This method returns a pointer to the appropriate NativeMetafile object
+  // according to the platform.
+  static printing::NativeMetafile* CreateMetafile();
+
+ private:
+  NativeMetafileFactory();
+  DISALLOW_COPY_AND_ASSIGN(NativeMetafileFactory);
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_NATIVE_METAFILE_FACTORY_H_
diff --git a/printing/native_metafile_linux.h b/printing/native_metafile_linux.h
new file mode 100644
index 0000000..9fe622b
--- /dev/null
+++ b/printing/native_metafile_linux.h
@@ -0,0 +1,81 @@
+// Copyright (c) 2011 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 PRINTING_NATIVE_METAFILE_LINUX_H_
+#define PRINTING_NATIVE_METAFILE_LINUX_H_
+
+#include "base/basictypes.h"
+
+typedef struct _cairo_surface cairo_surface_t;
+typedef struct _cairo cairo_t;
+
+namespace base {
+struct FileDescriptor;
+}
+
+class FilePath;
+
+namespace printing {
+
+// This class is used to generate a PDF stream and to  store rendering results
+// in a string buffer.
+class NativeMetafile {
+ public:
+  virtual ~NativeMetafile() {}
+
+  // Initializes to a fresh new metafile. Returns true on success.
+  // Note: It should only be called from the renderer process to allocate
+  // rendering resources.
+  virtual bool Init() = 0;
+
+  // Initializes a copy of metafile from PDF stream data.
+  // Returns true on success.
+  // |src_buffer| should point to the shared memory which stores PDF
+  // contents generated in the renderer.
+  // Note: It should only be called from the browser process to initialize
+  // |data_|.
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size) = 0;
+
+  // Sets raw PDF data for the document. This is used when a cairo drawing
+  // surface has already been created. This method will cause all subsequent
+  // drawing on the surface to be discarded (in Close()). If Init() has not yet
+  // been called this method simply calls the second version of Init.
+  virtual bool SetRawData(const void* src_buffer, uint32 src_buffer_size) = 0;
+
+  // Prepares a new cairo surface/context for rendering a new page.
+  // The unit is in point (=1/72 in).
+  // Returns NULL when failed.
+  virtual cairo_t* StartPage(double width_in_points,
+                             double height_in_points,
+                             double margin_top_in_points,
+                             double margin_right_in_points,
+                             double margin_bottom_in_points,
+                             double margin_left_in_points) = 0;
+
+  // Destroys the surface and the context used in rendering current page.
+  // The results of current page will be appended into buffer |data_|.
+  // Returns true on success.
+  virtual bool FinishPage() = 0;
+
+  // Closes resulting PDF file. No further rendering is allowed.
+  virtual void Close() = 0;
+
+  // Returns size of PDF contents stored in buffer |data_|.
+  // This function should ONLY be called after PDF file is closed.
+  virtual uint32 GetDataSize() const = 0;
+
+  // Copies PDF contents stored in buffer |data_| into |dst_buffer|.
+  // This function should ONLY be called after PDF file is closed.
+  // Returns true only when success.
+  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
+
+  // Saves PDF contents stored in buffer |data_| into the file
+  // associated with |fd|.
+  // This function should ONLY be called after PDF file is closed.
+  virtual bool SaveTo(const base::FileDescriptor& fd) const = 0;
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_NATIVE_METAFILE_LINUX_H_
diff --git a/printing/native_metafile_mac.h b/printing/native_metafile_mac.h
new file mode 100644
index 0000000..940da50
--- /dev/null
+++ b/printing/native_metafile_mac.h
@@ -0,0 +1,90 @@
+// Copyright (c) 2011 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 PRINTING_NATIVE_METAFILE_MAC_H_
+#define PRINTING_NATIVE_METAFILE_MAC_H_
+
+#include <ApplicationServices/ApplicationServices.h>
+#include <CoreFoundation/CoreFoundation.h>
+
+#include "base/basictypes.h"
+#include "base/mac/scoped_cftyperef.h"
+
+namespace gfx {
+class Rect;
+class Size;
+class Point;
+}
+class FilePath;
+
+namespace printing {
+
+// This class creates a graphics context that renders into a PDF data stream.
+class NativeMetafile {
+ public:
+
+  virtual ~NativeMetafile() {}
+
+  // Initializes a new metafile, and returns a drawing context for rendering
+  // into the PDF. Returns NULL on failure.
+  // Note: The returned context *must not be retained* past Close(). If it is,
+  // the data returned from GetData will not be valid PDF data.
+  virtual CGContextRef Init() = 0;
+
+  // Initializes a copy of metafile from PDF data. Returns true on success.
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size) = 0;
+
+  // Prepares a new pdf page at specified |content_origin| with the given
+  // |page_size| and a |scale_factor| to use for the drawing.
+  virtual CGContextRef StartPage(const gfx::Size& page_size,
+                         const gfx::Point& content_origin,
+                         const float& scale_factor) = 0;
+
+  // Closes the current page.
+  virtual void FinishPage() = 0;
+
+  // Closes the PDF file; no further rendering is allowed.
+  virtual void Close() = 0;
+
+  // Renders the given page into |rect| in the given context.
+  // Pages use a 1-based index. The rendering uses the following arguments
+  // to determine scaling and translation factors.
+  // |shrink_to_fit| specifies whether the output should be shrunk to fit the
+  // supplied |rect| if the page size is larger than |rect| in any dimension.
+  // If this is false, parts of the PDF page that lie outside the bounds will be
+  // clipped.
+  // |stretch_to_fit| specifies whether the output should be stretched to fit
+  // the supplied bounds if the page size is smaller than |rect| in all
+  // dimensions.
+  // |center_horizontally| specifies whether the final image (after any scaling
+  // is done) should be centered horizontally within the given |rect|.
+  // |center_vertically| specifies whether the final image (after any scaling
+  // is done) should be centered vertically within the given |rect|.
+  // Note that all scaling preserves the original aspect ratio of the page.
+  virtual bool RenderPage(unsigned int page_number, CGContextRef context,
+                  const CGRect rect, bool shrink_to_fit, bool stretch_to_fit,
+                  bool center_horizontally, bool center_vertically) const = 0;
+  virtual unsigned int GetPageCount() const = 0;
+
+  // Returns the bounds of the given page.
+  // Pages use a 1-based index.
+  virtual gfx::Rect GetPageBounds(unsigned int page_number) const = 0;
+
+  // Returns the size of the underlying PDF data. Only valid after Close() has
+  // been called.
+  virtual uint32 GetDataSize() const = 0;
+
+  // Copies the first |dst_buffer_size| bytes of the PDF data into |dst_buffer|.
+  // Only valid after Close() has been called.
+  // Returns true if the copy succeeds.
+  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
+
+  // Saves the raw PDF data to the given file. For testing only.
+  // Returns true if writing succeeded.
+  virtual bool SaveTo(const FilePath& file_path) const = 0;
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_NATIVE_METAFILE_MAC_H_
diff --git a/printing/native_metafile_win.h b/printing/native_metafile_win.h
new file mode 100644
index 0000000..fa00121
--- /dev/null
+++ b/printing/native_metafile_win.h
@@ -0,0 +1,103 @@
+// Copyright (c) 2011 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 PRINTING_NATIVE_METAFILE_WIN_H_
+#define PRINTING_NATIVE_METAFILE_WIN_H_
+
+#include <windows.h>
+#include <vector>
+
+#include "base/basictypes.h"
+
+class FilePath;
+
+namespace gfx {
+class Rect;
+}
+
+namespace printing {
+
+// Simple wrapper class that manages a data stream and its virtual HDC.
+class NativeMetafile {
+ public:
+  virtual ~NativeMetafile() {}
+
+  // Initializes the data stream with the data in |src_buffer|. Returns
+  // true on success.
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size) = 0;
+
+  // Generates a virtual HDC that will record every GDI commands and compile it
+  // in a EMF data stream.
+  // hdc is used to setup the default DPI and color settings. hdc is optional.
+  // rect specifies the dimensions (in .01-millimeter units) of the EMF. rect is
+  // optional.
+  virtual bool CreateDc(HDC sibling, const RECT* rect) = 0;
+
+  // Similar to the above method but the metafile is backed by a file.
+  virtual bool CreateFileBackedDc(HDC sibling,
+                                  const RECT* rect,
+                                  const FilePath& path) = 0;
+
+  // Load a data stream from file.
+  virtual bool CreateFromFile(const FilePath& metafile_path) = 0;
+
+  // TODO(maruel): CreateFromFile(). If ever used. Maybe users would like to
+  // have the ability to save web pages to an EMF file? Afterward, it is easy to
+  // convert to PDF.
+
+  // Closes the HDC created by CreateDc() and generates the compiled EMF
+  // data.
+  virtual bool CloseDc() = 0;
+
+  // Closes the EMF data handle when it is not needed anymore.
+  virtual void CloseEmf() = 0;
+
+  // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
+  // original GDI function that were called when recording the EMF. |rect| is in
+  // "logical units" and is optional. If |rect| is NULL, the natural EMF bounds
+  // are used.
+  // Note: Windows has been known to have stack buffer overflow in its GDI
+  // functions, whether used directly or indirectly through precompiled EMF
+  // data. We have to accept the risk here. Since it is used only for printing,
+  // it requires user intervention.
+  virtual bool Playback(HDC hdc, const RECT* rect) const = 0;
+
+  // The slow version of Playback(). It enumerates all the records and play them
+  // back in the HDC. The trick is that it skip over the records known to have
+  // issue with some printers. See Emf::Record::SafePlayback implementation for
+  // details.
+  virtual bool SafePlayback(HDC hdc) const = 0;
+
+  // Retrieves the bounds of the painted area by this EMF buffer. This value
+  // should be passed to Playback to keep the exact same size.
+  virtual gfx::Rect GetBounds() const = 0;
+
+  // Retrieves the data stream size.
+  virtual uint32 GetDataSize() const = 0;
+
+  // Retrieves the data stream.
+  virtual bool GetData(void* buffer, uint32 size) const = 0;
+
+  // Retrieves the data stream. It is an helper function.
+  virtual bool GetData(std::vector<uint8>* buffer) const = 0;
+
+  virtual HENHMETAFILE emf() const = 0;
+
+  virtual HDC hdc() const = 0;
+
+  // Inserts a custom GDICOMMENT records indicating StartPage/EndPage calls
+  // (since StartPage and EndPage do not work in a metafile DC). Only valid
+  // when hdc_ is non-NULL.
+  virtual bool StartPage() = 0;
+  virtual bool EndPage() = 0;
+
+  // Saves the EMF data to a file as-is. It is recommended to use the .emf file
+  // extension but it is not enforced. This function synchronously writes to the
+  // file. For testing only.
+  virtual bool SaveTo(const std::wstring& filename) const = 0;
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_NATIVE_METAFILE_WIN_H_
diff --git a/printing/pdf_metafile_mac.h b/printing/pdf_metafile_mac.h
index 557b008..c5669a8 100644
--- a/printing/pdf_metafile_mac.h
+++ b/printing/pdf_metafile_mac.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -9,7 +9,9 @@
 #include <CoreFoundation/CoreFoundation.h>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
 #include "base/mac/scoped_cftyperef.h"
+#include "printing/native_metafile_mac.h"
 
 namespace gfx {
 class Rect;
@@ -21,36 +23,31 @@ class FilePath;
 namespace printing {
 
 // This class creates a graphics context that renders into a PDF data stream.
-class PdfMetafile {
+class PdfMetafile : public NativeMetafile {
  public:
-  // To create PDF data, callers should also call Init() to set up the
-  // rendering context.
-  // To create a metafile from existing Data, callers should also call
-  // Init(const void*, uint32).
-  PdfMetafile();
 
-  ~PdfMetafile();
+  virtual ~PdfMetafile();
 
   // Initializes a new metafile, and returns a drawing context for rendering
   // into the PDF. Returns NULL on failure.
   // Note: The returned context *must not be retained* past Close(). If it is,
   // the data returned from GetData will not be valid PDF data.
-  CGContextRef Init();
+  virtual CGContextRef Init();
 
   // Initializes a copy of metafile from PDF data. Returns true on success.
-  bool Init(const void* src_buffer, uint32 src_buffer_size);
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size);
 
   // Prepares a new pdf page at specified |content_origin| with the given
   // |page_size| and a |scale_factor| to use for the drawing.
-  CGContextRef StartPage(const gfx::Size& page_size,
+  virtual CGContextRef StartPage(const gfx::Size& page_size,
                          const gfx::Point& content_origin,
                          const float& scale_factor);
 
   // Closes the current page.
-  void FinishPage();
+  virtual void FinishPage();
 
   // Closes the PDF file; no further rendering is allowed.
-  void Close();
+  virtual void Close();
 
   // Renders the given page into |rect| in the given context.
   // Pages use a 1-based index. The rendering uses the following arguments
@@ -67,29 +64,39 @@ class PdfMetafile {
   // |center_vertically| specifies whether the final image (after any scaling
   // is done) should be centered vertically within the given |rect|.
   // Note that all scaling preserves the original aspect ratio of the page.
-  bool RenderPage(unsigned int page_number, CGContextRef context,
+  virtual bool RenderPage(unsigned int page_number, CGContextRef context,
                   const CGRect rect, bool shrink_to_fit, bool stretch_to_fit,
                   bool center_horizontally, bool center_vertically) const;
-  unsigned int GetPageCount() const;
+  virtual unsigned int GetPageCount() const;
 
   // Returns the bounds of the given page.
   // Pages use a 1-based index.
-  gfx::Rect GetPageBounds(unsigned int page_number) const;
+  virtual  gfx::Rect GetPageBounds(unsigned int page_number) const;
 
   // Returns the size of the underlying PDF data. Only valid after Close() has
   // been called.
-  uint32 GetDataSize() const;
+  virtual uint32 GetDataSize() const;
 
   // Copies the first |dst_buffer_size| bytes of the PDF data into |dst_buffer|.
   // Only valid after Close() has been called.
   // Returns true if the copy succeeds.
-  bool GetData(void* dst_buffer, uint32 dst_buffer_size) const;
+  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const;
 
   // Saves the raw PDF data to the given file. For testing only.
   // Returns true if writing succeeded.
-  bool SaveTo(const FilePath& file_path) const;
+  virtual bool SaveTo(const FilePath& file_path) const;
+
+ protected:
+  // To create PDF data, callers should call Init() to set up the rendering
+  // context.
+  // To create a metafile from existing data, callers should call
+  // Init(const void*, uint32).
+  PdfMetafile();
 
  private:
+  friend class NativeMetafileFactory;
+  FRIEND_TEST_ALL_PREFIXES(PdfMetafileTest, Pdf);
+
   // Returns a CGPDFDocumentRef version of pdf_data_.
   CGPDFDocumentRef GetPDFDocument() const;
 
diff --git a/printing/pdf_metafile_mac_unittest.cc b/printing/pdf_metafile_mac_unittest.cc
index ec8cd3a..8b52b06 100644
--- a/printing/pdf_metafile_mac_unittest.cc
+++ b/printing/pdf_metafile_mac_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -12,6 +12,8 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/rect.h"
 
+namespace printing {
+
 TEST(PdfMetafileTest, Pdf) {
   // Test in-renderer constructor.
   printing::PdfMetafile pdf;
@@ -60,3 +62,5 @@ TEST(PdfMetafileTest, Pdf) {
   EXPECT_EQ(720, page_size.width());
   EXPECT_EQ(540, page_size.height());
 }
+
+}  // namespace printing
diff --git a/printing/pdf_ps_metafile_cairo.h b/printing/pdf_ps_metafile_cairo.h
index 7274dd8..645a462 100644
--- a/printing/pdf_ps_metafile_cairo.h
+++ b/printing/pdf_ps_metafile_cairo.h
@@ -8,6 +8,8 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
+#include "printing/native_metafile_linux.h"
 
 typedef struct _cairo_surface cairo_surface_t;
 typedef struct _cairo cairo_t;
@@ -22,59 +24,58 @@ namespace printing {
 
 // This class uses Cairo graphics library to generate PostScript/PDF stream
 // and stores rendering results in a string buffer.
-class PdfPsMetafile {
+class PdfPsMetafile : public NativeMetafile  {
  public:
-  PdfPsMetafile();
-  ~PdfPsMetafile();
+  virtual ~PdfPsMetafile();
 
   // Initializes to a fresh new metafile. Returns true on success.
   // Note: Only call in the renderer to allocate rendering resources.
-  bool Init();
+  virtual bool Init();
 
   // Initializes a copy of metafile from PDF stream data.
   // Returns true on success.
   // |src_buffer| should point to the shared memory which stores PDF
   // contents generated in the renderer.
   // Note: Only call in the browser to initialize |data_|.
-  bool Init(const void* src_buffer, uint32 src_buffer_size);
+  virtual bool Init(const void* src_buffer, uint32 src_buffer_size);
 
   // Sets raw PDF data for the document. This is used when a cairo drawing
   // surface has already been created. This method will cause all subsequent
   // drawing on the surface to be discarded (in Close()). If Init() has not yet
   // been called this method simply calls the second version of Init.
-  bool SetRawData(const void* src_buffer, uint32 src_buffer_size);
+  virtual bool SetRawData(const void* src_buffer, uint32 src_buffer_size);
 
   // Prepares a new cairo surface/context for rendering a new page.
   // The unit is in point (=1/72 in).
   // Returns NULL when failed.
-  cairo_t* StartPage(double width_in_points,
-                     double height_in_points,
-                     double margin_top_in_points,
-                     double margin_right_in_points,
-                     double margin_bottom_in_points,
-                     double margin_left_in_points);
+  virtual cairo_t* StartPage(double width_in_points,
+                             double height_in_points,
+                             double margin_top_in_points,
+                             double margin_right_in_points,
+                             double margin_bottom_in_points,
+                             double margin_left_in_points);
 
   // Destroys the surface and the context used in rendering current page.
   // The results of current page will be appended into buffer |data_|.
   // Returns true on success.
-  bool FinishPage();
+  virtual bool FinishPage();
 
   // Closes resulting PDF file. No further rendering is allowed.
-  void Close();
+  virtual void Close();
 
   // Returns size of PDF contents stored in buffer |data_|.
   // This function should ONLY be called after PDF file is closed.
-  uint32 GetDataSize() const;
+  virtual uint32 GetDataSize() const;
 
   // Copies PDF contents stored in buffer |data_| into |dst_buffer|.
   // This function should ONLY be called after PDF file is closed.
   // Returns true only when success.
-  bool GetData(void* dst_buffer, uint32 dst_buffer_size) const;
+  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const;
 
   // Saves PDF contents stored in buffer |data_| into the file
   // associated with |fd|.
   // This function should ONLY be called after PDF file is closed.
-  bool SaveTo(const base::FileDescriptor& fd) const;
+  virtual bool SaveTo(const base::FileDescriptor& fd) const;
 
   // The hardcoded margins, in points. These values are based on 72 dpi,
   // with 0.25 margins on top, left, and right, and 0.56 on bottom.
@@ -87,7 +88,13 @@ class PdfPsMetafile {
   // if the context was not created by a PdfPsMetafile object.
   static PdfPsMetafile* FromCairoContext(cairo_t* context);
 
+ protected:
+  PdfPsMetafile();
+
  private:
+  friend class NativeMetafileFactory;
+  FRIEND_TEST_ALL_PREFIXES(PdfPsTest, Pdf);
+
   // Cleans up all resources.
   void CleanUpAll();
 
diff --git a/printing/pdf_ps_metafile_cairo_unittest.cc b/printing/pdf_ps_metafile_cairo_unittest.cc
index b7ed449..a3442c8 100644
--- a/printing/pdf_ps_metafile_cairo_unittest.cc
+++ b/printing/pdf_ps_metafile_cairo_unittest.cc
@@ -15,6 +15,8 @@
 
 typedef struct _cairo cairo_t;
 
+namespace {
+
 class PdfPsTest : public testing::Test {
  protected:
   base::FileDescriptor DevNullFD() {
@@ -22,6 +24,10 @@ class PdfPsTest : public testing::Test {
   }
 };
 
+}  // namespace
+
+namespace printing {
+
 TEST_F(PdfPsTest, Pdf) {
   // Tests in-renderer constructor.
   printing::PdfPsMetafile pdf;
@@ -81,3 +87,5 @@ TEST_F(PdfPsTest, Pdf) {
   pdf3.GetData(WriteInto(&output, size + 1), size);
   EXPECT_EQ(test_raw_data, output);
 }
+
+}  // namespace printing
diff --git a/printing/print_settings_initializer_gtk.cc b/printing/print_settings_initializer_gtk.cc
index 60ab530..8a62929 100644
--- a/printing/print_settings_initializer_gtk.cc
+++ b/printing/print_settings_initializer_gtk.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -9,7 +9,7 @@
 
 #include "base/string_piece.h"
 #include "base/utf_string_conversions.h"
-#include "printing/native_metafile.h"
+#include "printing/pdf_ps_metafile_cairo.h"
 #include "printing/print_settings.h"
 #include "printing/units.h"
 
@@ -58,19 +58,19 @@ void PrintSettingsInitializerGtk::InitPrintSettings(
     double page_width_in_pixel = 8.5 * dpi;
     double page_height_in_pixel = 11.0 * dpi;
     physical_size_device_units.SetSize(
-      static_cast<int>(page_width_in_pixel),
-      static_cast<int>(page_height_in_pixel));
+        static_cast<int>(page_width_in_pixel),
+        static_cast<int>(page_height_in_pixel));
     printable_area_device_units.SetRect(
-      static_cast<int>(
-          NativeMetafile::kLeftMarginInInch * dpi),
-      static_cast<int>(
-          NativeMetafile::kTopMarginInInch * dpi),
-      page_width_in_pixel -
-      (NativeMetafile::kLeftMarginInInch +
-       NativeMetafile::kRightMarginInInch) * dpi,
-      page_height_in_pixel -
-      (NativeMetafile::kTopMarginInInch +
-       NativeMetafile::kBottomMarginInInch) * dpi);
+        static_cast<int>(
+            PdfPsMetafile::kLeftMarginInInch * dpi),
+        static_cast<int>(
+            PdfPsMetafile::kTopMarginInInch * dpi),
+        page_width_in_pixel -
+            (PdfPsMetafile::kLeftMarginInInch +
+             PdfPsMetafile::kRightMarginInInch) * dpi,
+        page_height_in_pixel -
+            (PdfPsMetafile::kTopMarginInInch +
+             PdfPsMetafile::kBottomMarginInInch) * dpi);
   }
 
   print_settings->set_dpi(dpi);
diff --git a/printing/printed_document.h b/printing/printed_document.h
index f95ddcf..14e5e8c 100644
--- a/printing/printed_document.h
+++ b/printing/printed_document.h
@@ -13,7 +13,6 @@
 #include "base/synchronization/lock.h"
 #include "googleurl/src/gurl.h"
 #include "printing/print_settings.h"
-#include "printing/native_metafile.h"
 #include "ui/gfx/native_widget_types.h"
 
 class FilePath;
@@ -25,6 +24,7 @@ class Font;
 
 namespace printing {
 
+class NativeMetafile;
 class PrintedPage;
 class PrintedPagesSource;
 class PrintingContext;
diff --git a/printing/printing.gyp b/printing/printing.gyp
index 270306f..9201e69 100644
--- a/printing/printing.gyp
+++ b/printing/printing.gyp
@@ -1,4 +1,4 @@
-# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+# Copyright (c) 2011 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.
 
@@ -36,6 +36,11 @@
         'image_mac.cc',
         'image_win.cc',
         'image.h',
+        'native_metafile_factory.cc',
+        'native_metafile_factory.h',
+        'native_metafile_linux.h',
+        'native_metafile_mac.h',
+        'native_metafile_win.h',
         'native_metafile.h',
         'page_number.cc',
         'page_number.h',
diff --git a/printing/printing_context_cairo.cc b/printing/printing_context_cairo.cc
index d0110b1..84aaa64 100644
--- a/printing/printing_context_cairo.cc
+++ b/printing/printing_context_cairo.cc
@@ -9,7 +9,9 @@
 
 #if defined(OS_CHROMEOS)
 #include <unicode/ulocdata.h>
-#include <printing/native_metafile.h>
+
+#include "printing/native_metafile.h"
+#include "printing/pdf_ps_metafile_cairo.h"
 #else
 #include <gtk/gtk.h>
 #include <gtk/gtkprintunixdialog.h>
@@ -119,12 +121,12 @@ PrintingContext::Result PrintingContextCairo::UseDefaultSettings() {
 
   physical_size_device_units.SetSize(width, height);
   printable_area_device_units.SetRect(
-      static_cast<int>(NativeMetafile::kLeftMarginInInch * dpi),
-      static_cast<int>(NativeMetafile::kTopMarginInInch * dpi),
-      width - (NativeMetafile::kLeftMarginInInch +
-          NativeMetafile::kRightMarginInInch) * dpi,
-      height - (NativeMetafile::kTopMarginInInch +
-          NativeMetafile::kBottomMarginInInch) * dpi);
+      static_cast<int>(PdfPsMetafile::kLeftMarginInInch * dpi),
+      static_cast<int>(PdfPsMetafile::kTopMarginInInch * dpi),
+      width - (PdfPsMetafile::kLeftMarginInInch +
+          PdfPsMetafile::kRightMarginInInch) * dpi,
+      height - (PdfPsMetafile::kTopMarginInInch +
+          PdfPsMetafile::kBottomMarginInInch) * dpi);
 
   settings_.set_dpi(dpi);
   settings_.SetPrinterPrintableArea(physical_size_device_units,