Make PluginInstance::PrintPDFOutput-metafile implementation agnostic on Linux.

printing/pdf_ps_metafile_cairo.h

Index: printing/pdf_ps_metafile_cairo.h
diff --git a/printing/pdf_ps_metafile_cairo.h b/printing/pdf_ps_metafile_cairo.h
index 2ae1f349a158c01164eaab5d7c7a70a734f2b628..6d5cf5ce7f083cad77c148a3b045d1841fbc3f58 100644
--- a/printing/pdf_ps_metafile_cairo.h
+++ b/printing/pdf_ps_metafile_cairo.h
@@ -58,10 +58,6 @@ class PdfPsMetafile : public NativeMetafile {
   virtual bool SaveToFD(const base::FileDescriptor& fd) const;
 #endif  // if defined(OS_CHROMEOS)
 
-  // Returns the PdfPsMetafile object that owns the given context. Returns NULL
-  // if the context was not created by a PdfPsMetafile object.
-  static PdfPsMetafile* FromCairoContext(cairo_t* context);
-
  protected:
   PdfPsMetafile();