Fix an assert statement in SkPngCodec

tests/CodecTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkAndroidCodec.h"
 #include "SkBitmap.h"
@@ skipping 1284 matching lines @@
             continue;
         }
 
         // Scanline decoding should not require a rewind.
         SkCodec::Result result = codec->startScanlineDecode(info);
         if (SkCodec::kSuccess != result) {
             ERRORF(r, "Scanline decoding failed for %s with %i", file, result);
         }
     }
 }
+
+// This test verifies that we fixed an assert statement that fired when reusing a png codec
+// after scaling.
+DEF_TEST(Codec_reusePng, r) {
+    std::unique_ptr<SkStream> stream(GetResourceAsStream("plane.png"));
+    if (!stream) {
+        return;
+    }
+
+    std::unique_ptr<SkAndroidCodec> codec(SkAndroidCodec::NewFromStream(stream.release()));
+    if (!codec) {
+        ERRORF(r, "Failed to create codec\n");
+        return;
+    }
+
+    SkAndroidCodec::AndroidOptions opts;
+    opts.fSampleSize = 5;
+    auto size = codec->getSampledDimensions(opts.fSampleSize);
+    auto info = codec->getInfo().makeWH(size.fWidth, size.fHeight).makeColorType(kN32_SkColorType);
+    SkBitmap bm;
+    bm.allocPixels(info);
+    auto result = codec->getAndroidPixels(info, bm.getPixels(), bm.rowBytes(), &opts);
+    REPORTER_ASSERT(r, result == SkCodec::kSuccess);
+
+    info = codec->getInfo().makeColorType(kN32_SkColorType);
+    bm.allocPixels(info);
+    opts.fSampleSize = 1;
+    result = codec->getAndroidPixels(info, bm.getPixels(), bm.rowBytes(), &opts);
+    REPORTER_ASSERT(r, result == SkCodec::kSuccess);
+}