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

src/effects/SkPictureImageFilter.cpp

Index: src/effects/SkPictureImageFilter.cpp
diff --git a/src/effects/SkPictureImageFilter.cpp b/src/effects/SkPictureImageFilter.cpp
index d85024e2254289e803ad1dd2a6405e62140ae448..d1a7fc59cf6cc9bfb697e355a9ebb074bb3ea00c 100644
--- a/src/effects/SkPictureImageFilter.cpp
+++ b/src/effects/SkPictureImageFilter.cpp
@@ -84,8 +84,9 @@ void SkPictureImageFilter::flatten(SkWriteBuffer& buffer) const {
     }
 }
 
-bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const Context& ctx,
-                                         SkBitmap* result, SkIPoint* offset) const {
+bool SkPictureImageFilter::onFilterImageDeprecated(Proxy* proxy, const SkBitmap&,
+                                                   const Context& ctx,
+                                                   SkBitmap* result, SkIPoint* offset) const {
     if (!fPicture) {
         offset->fX = offset->fY = 0;
         return true;