Create a Factory for NativeMetafile.

printing/metafile_factory.h

+// 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.
+
+#ifndef METAFILE_FACTORY_H_
+#define METAFILE_FACTORY_H_
+
+#include "base/basictypes.h"
+#include "printing/native_metafile.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 {
+
+// This class is used to obtain pointers to NativeMetafile objects. It is the
+// only way to initialize such objects since their constructors are private.
+class MetafileFactory {
+ public:
+  virtual ~MetafileFactory();
+
+  // This method takes care of returning a pointer to the appropriate
+  // NativeMetafile object according to the platform.
+  static printing::NativeMetafile* GetMetafile();
+
+#if defined(OS_LINUX)
+  static printing::NativeMetafile*
+    GetMetafileFrom(cairo_t* context);
+#endif
+
+ private:
+  MetafileFactory();
+  DISALLOW_COPY_AND_ASSIGN(MetafileFactory);
+};
+
+}  // namespace printing
+
+#endif /* METAFILE_FACTORY_H_ */