Report 0 rowsDecoded for no rows (SkPngCodec interlaced)

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 1314 matching lines @@
     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);
 }
+
+DEF_TEST(Codec_rowsDecoded, r) {
+    auto file = "plane_interlaced.png";
+    std::unique_ptr<SkStream> stream(GetResourceAsStream(file));
+    if (!stream) {
+        return;
+    }
+
+    // This is enough to read the header etc, but no rows.
+    auto data = SkData::MakeFromStream(stream.get(), 99);
+    std::unique_ptr<SkCodec> codec(SkCodec::NewFromData(data));
+    if (!codec) {
+        ERRORF(r, "Failed to create codec\n");
+        return;
+    }
+
+    auto info = codec->getInfo().makeColorType(kN32_SkColorType);
+    SkBitmap bm;
+    bm.allocPixels(info);
+    auto result = codec->startIncrementalDecode(info, bm.getPixels(), bm.rowBytes());
+    REPORTER_ASSERT(r, result == SkCodec::kSuccess);
+
+    // This is an arbitrary value. The important fact is that it is not zero, and rowsDecoded
+    // should get set to zero by incrementalDecode.
+    int rowsDecoded = 77;
+    result = codec->incrementalDecode(&rowsDecoded);
+    REPORTER_ASSERT(r, result == SkCodec::kIncompleteInput);
+    REPORTER_ASSERT(r, rowsDecoded == 0);
+}