Mark existing image filter entry points that will be going away with Deprecated

src/effects/SkTestImageFilters.cpp

Index: src/effects/SkTestImageFilters.cpp
diff --git a/src/effects/SkTestImageFilters.cpp b/src/effects/SkTestImageFilters.cpp
index 432b576c15aeef184d671a4e3b186ba3b9c2083d..b8b0e187ede4452ff3523e56fed8b445b3279fa2 100755
--- a/src/effects/SkTestImageFilters.cpp
+++ b/src/effects/SkTestImageFilters.cpp
@@ -27,9 +27,9 @@ public:
 
 ///////////////////////////////////////////////////////////////////////////////
 
-bool SkDownSampleImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
-                                            const Context&,
-                                            SkBitmap* result, SkIPoint*) const {
+bool SkDownSampleImageFilter::onFilterImageDeprecated(Proxy* proxy, const SkBitmap& src,
+                                                      const Context&,
+                                                      SkBitmap* result, SkIPoint*) const {
     SkScalar scale = fScale;
     if (scale > SK_Scalar1 || scale <= 0) {
         return false;