Fix rewinding bug in SkJpegCodec

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 994 matching lines @@
     // Now test an image which is too big. Any image with a larger header (i.e.
     // has bigger width/height) is also too big.
     const unsigned char tooBigWbmp[] = { 0x00, 0x00,           // Header
                                          0x84, 0x80, 0x00,     // W: 65536
                                          0x84, 0x80, 0x00 };   // H: 65536
     stream.reset(new SkMemoryStream(tooBigWbmp, sizeof(tooBigWbmp), false));
     codec.reset(SkCodec::NewFromStream(stream.release()));
 
     REPORTER_ASSERT(r, !codec);
 }
+
+DEF_TEST(Codec_jpeg_rewind, r) {
+    const char* path = "mandrill_512_q075.jpg";
+    SkAutoTDelete<SkStream> stream(resource(path));
+    if (!stream) {
+        SkDebugf("Missing resource '%s'\n", path);
+        return;
+    }
+    SkAutoTDelete<SkAndroidCodec> codec(SkAndroidCodec::NewFromStream(stream.release()));
+    if (!codec) {
+        ERRORF(r, "Unable to create codec '%s'.", path);
+        return;
+    }
+
+    const int width = codec->getInfo().width();
+    const int height = codec->getInfo().height();
+    size_t rowBytes = sizeof(SkPMColor) * width;
+    SkAutoMalloc pixelStorage(height * rowBytes);
+
+    // Perform a sampled decode.
+    SkAndroidCodec::AndroidOptions opts;
+    opts.fSampleSize = 12;
+    codec->getAndroidPixels(codec->getInfo().makeWH(width / 12, height / 12), pixelStorage.get(),
+                            rowBytes, &opts);
+
+    // Rewind the codec and perform a full image decode.
+    SkCodec::Result result = codec->getPixels(codec->getInfo(), pixelStorage.get(), rowBytes);
+    REPORTER_ASSERT(r, SkCodec::kSuccess == result);
+}