Guarded shrink setting with ifdefs to make clear where it is used.

printing/printed_document.h

Index: printing/printed_document.h
diff --git a/printing/printed_document.h b/printing/printed_document.h
index b8af4bb5f39e4984cf98d0d4278f7dc222176bd4..3341d54221ab179411da6d08dab345e7052bcfd8 100644
--- a/printing/printed_document.h
+++ b/printing/printed_document.h
@@ -42,8 +42,13 @@ class PRINTING_EXPORT PrintedDocument
 
   // Sets a page's data. 0-based. Takes metafile ownership.
   // Note: locks for a short amount of time.
-  void SetPage(int page_number, Metafile* metafile, double shrink,
-               const gfx::Size& paper_size, const gfx::Rect& page_rect);
+  void SetPage(int page_number,
+               Metafile* metafile,
+#if defined(OS_WIN)
+               double shrink,
+#endif  // OS_WIN
+               const gfx::Size& paper_size,
+               const gfx::Rect& page_rect);
 
   // Retrieves a page. If the page is not available right now, it
   // requests to have this page be rendered and returns false.