Clean up SkImageFilter constructors.

include/effects/SkTestImageFilters.h

Index: include/effects/SkTestImageFilters.h
diff --git a/include/effects/SkTestImageFilters.h b/include/effects/SkTestImageFilters.h
index 4b20936c3bf39e28bc4bbce80e6116fe65fd31ea..28360403715abb9fe55d0d7b827e0ca547e5858b 100644
--- a/include/effects/SkTestImageFilters.h
+++ b/include/effects/SkTestImageFilters.h
@@ -7,14 +7,15 @@
 // Fun mode that scales down (only) and then scales back up to look pixelated
 class SK_API SkDownSampleImageFilter : public SkImageFilter {
 public:
-    static SkDownSampleImageFilter* Create(SkScalar scale) {
-        return SkNEW_ARGS(SkDownSampleImageFilter, (scale));
+    static SkDownSampleImageFilter* Create(SkScalar scale, SkImageFilter* input = NULL) {
+        return SkNEW_ARGS(SkDownSampleImageFilter, (scale, input));
     }
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDownSampleImageFilter)
 
 protected:
-    SkDownSampleImageFilter(SkScalar scale) : INHERITED(0), fScale(scale) {}
+    SkDownSampleImageFilter(SkScalar scale, SkImageFilter* input)
+      : INHERITED(1, &input), fScale(scale) {}
     SkDownSampleImageFilter(SkReadBuffer& buffer);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;