Update MagnifierImageFilter to sk_sp

fuzz/FilterFuzz.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "Fuzz.h"
 #include "Sk1DPathEffect.h"
 #include "Sk2DPathEffect.h"
 #include "SkAlphaThresholdFilter.h"
@@ skipping 561 matching lines @@
         filter = cf ? SkColorFilterImageFilter::Make(std::move(cf), make_image_filter())
                     : nullptr;
         break;
     }
     case BLUR:
         filter = SkBlurImageFilter::Make(make_scalar(true),
                                          make_scalar(true),
                                          make_image_filter());
         break;
     case MAGNIFIER:
-        filter = sk_sp<SkImageFilter>(SkMagnifierImageFilter::Create(make_rect(),
-                                                                     make_scalar(true)));
+        filter = SkMagnifierImageFilter::Make(make_rect(),
+                                              make_scalar(true), 
+                                              make_image_filter());

[f(malita), 2016/04/07 13:33:42]

Third arg should be nullptr for equivalence with existing code, but I presume
this is intended as a fix.

[robertphillips, 2016/04/07 14:02:05]

Right - I believe the prior behavior was incorrect.

         break;
     case DOWN_SAMPLE:
         filter = sk_sp<SkImageFilter>(SkDownSampleImageFilter::Create(make_scalar()));
         break;
     case XFERMODE:
         filter = SkXfermodeImageFilter::Make(SkXfermode::Make(make_xfermode()),
                                              make_image_filter(),
                                              make_image_filter(),
                                              nullptr);
         break;
@@ skipping 206 matching lines @@
 DEF_FUZZ(SerializedImageFilter, f) {
     fuzz = f;
     SkImageFilter* filter = make_serialized_image_filter();
 
     SkPaint paint;
     SkSafeUnref(paint.setImageFilter(filter));
     SkBitmap bitmap;
     SkCanvas canvas(bitmap);
     drawClippedBitmap(&canvas, 0, 0, paint);
 }