Begin removing deprecated (and now, unused) ImageFilter code paths

This CL focuses on removing the Proxy objects but takes some other stuff with it.

BUG=skia:4965
TBR=reed@google.com

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1896383003

Review URL: https://codereview.chromium.org/1896383003
diff --git a/src/effects/SkDisplacementMapEffect.cpp b/src/effects/SkDisplacementMapEffect.cpp
index b715f6a..c52b958 100644
--- a/src/effects/SkDisplacementMapEffect.cpp
+++ b/src/effects/SkDisplacementMapEffect.cpp
@@ -355,8 +355,7 @@
 
         offset->fX = bounds.left();
         offset->fY = bounds.top();
-        return SkSpecialImage::MakeFromGpu(source->internal_getProxy(),
-                                           SkIRect::MakeWH(bounds.width(), bounds.height()),
+        return SkSpecialImage::MakeFromGpu(SkIRect::MakeWH(bounds.width(), bounds.height()),
                                            kNeedNewImageUniqueID_SpecialImage,
                                            dst);
     }
@@ -393,8 +392,7 @@
 
     offset->fX = bounds.left();
     offset->fY = bounds.top();
-    return SkSpecialImage::MakeFromRaster(source->internal_getProxy(),
-                                          SkIRect::MakeWH(bounds.width(), bounds.height()),
+    return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(bounds.width(), bounds.height()),
                                           dst);
 }