Support multiple PDF rendering backends in the GM

R=epoger@google.com, vandebo@chromium.org

Review URL: https://codereview.chromium.org/21669004

git-svn-id: http://skia.googlecode.com/svn/trunk@10841 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gm.h b/gm/gm.h
index f806973..dbd7f42 100644
--- a/gm/gm.h
+++ b/gm/gm.h
@@ -42,6 +42,7 @@
             kSkip565_Flag               = 1 << 5,
             kSkipScaledReplay_Flag      = 1 << 6,
             kSkipGPU_Flag               = 1 << 7,
+            kSkipPDFRasterization_Flag  = 1 << 8,
         };
 
         void draw(SkCanvas*);