Fix swapped pixels in GifDecoder's output

third_party/gif_decoder/src/main/java/com/bumptech/glide/gifdecoder/StandardGifDecoder.java

@@ -766,8 +766,9 @@ private void decodeBitmapData(GifFrame frame) {
         } else if (code == endOfInformation) {
           break;
         } else if (oldCode == NULL_CODE) {
-          pixelStack[top] = suffix[code];
-          ++top;
+          mainPixels[pi] = suffix[code];
+          ++pi;
+          ++i;
           oldCode = code;
           first = code;
           continue;

third_party/gif_decoder/src/test/java/com/bumptech/glide/gifdecoder/GifDecoderTest.java

@@ -34,6 +34,21 @@ public void setUp() {
     provider = new MockProvider();
   }
 
+  @Test
+  public void testCorrectPixelsDecoded() throws IOException {
+    byte[] data = TestUtil.resourceToBytes(getClass(), "white_black_row.gif");
+    GifHeaderParser headerParser = new GifHeaderParser();
+    headerParser.setData(data);
+    GifHeader header = headerParser.parseHeader();
+    GifDecoder decoder = new StandardGifDecoder(provider);
+    decoder.setData(header, data);
+    decoder.advance();
+    Bitmap bitmap = decoder.getNextFrame();
+    assertNotNull(bitmap);
+    assertEquals(bitmap.getPixel(2, 0), bitmap.getPixel(0, 0));
+    assertEquals(bitmap.getPixel(3, 0), bitmap.getPixel(1, 0));
+  }
+
   @Test
   public void testCanDecodeFramesFromTestGif() throws IOException {
     byte[] data = TestUtil.resourceToBytes(getClass(), "partial_gif_decode.gif");