Fix printing project on linux.

printing/native_metafile.h

 // Copyright (c) 2009 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 "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
 
 #elif defined(OS_MACOSX)
 
-// TODO(port): Printing using PDF?
+// TODO(port): Printing using CG/PDF?
 // The mock class is here so we can compile.
-class NativeMetafile {};
+class NativeMetafile {
+ public:
+  int GetDataSize() const { return 0; }
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NativeMetafile);
+};
 
 #elif defined(OS_LINUX)
 
 #include "printing/pdf_ps_metafile_linux.h"
 
 namespace printing {
 
 typedef PdfPsMetafile NativeMetafile;
 
 }  // namespace printing
 
 #endif
 
 
 #endif  // PRINTING_NATIVE_METAFILE_H_