Add support to use Skia printing from Mac.

Reference the CG metafile from the Skia
version, so CG can be used to pass the PDF
data to the OS X pipeline.

If Skia is enabled as the Mac rendering engine,
generate Skia PDF files instead of CG ones.

This change adds a code path that will be enabled
in the future, but does not modify any existing
code, so there is no functional change.

BUG=79463
TEST=none

Review URL: http://codereview.chromium.org/7120006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90023 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/printing/pdf_metafile_skia.h b/printing/pdf_metafile_skia.h
index 3d1c7bd..2b8c7c1c 100644
--- a/printing/pdf_metafile_skia.h
+++ b/printing/pdf_metafile_skia.h
@@ -54,7 +54,15 @@
   virtual bool Playback(gfx::NativeDrawingContext hdc, const RECT* rect) const;
   virtual bool SafePlayback(gfx::NativeDrawingContext hdc) const;
   virtual HENHMETAFILE emf() const;
-#endif  // if defined(OS_WIN)
+#elif defined(OS_MACOSX)
+  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;
+#endif
 
 #if defined(OS_CHROMEOS)
   virtual bool SaveToFD(const base::FileDescriptor& fd) const;