Add deflate support to SkPDFStream.

Review URL: http://codereview.appspot.com/3326043

git-svn-id: http://skia.googlecode.com/svn/trunk@627 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/config/SkUserConfig.h b/include/config/SkUserConfig.h
index 8f63ce4..a2df745 100644
--- a/include/config/SkUserConfig.h
+++ b/include/config/SkUserConfig.h
@@ -117,6 +117,12 @@
  */
 //#define SK_SUPPORT_LCDTEXT
 
+/*  If zlib is available and you want to support the flate compression
+    algorithm (used in PDF generation), define SK_ZLIB_INCLUDE to be the
+    include path.
+ */
+//#define SK_ZLIB_INCLUDE <zlib.h>
+
 /*  If SK_DEBUG is defined, then you can optionally define SK_SUPPORT_UNITTEST
     which will run additional self-tests at startup. These can take a long time,
     so this flag is optional.