Fixes for partial images.

src/images/SkImageDecoder_libgif.cpp

Index: src/images/SkImageDecoder_libgif.cpp
diff --git a/src/images/SkImageDecoder_libgif.cpp b/src/images/SkImageDecoder_libgif.cpp
index 81071c95158be16957e20d3fdfb0ad3554ade7ce..e7122d76676ee3d7a5a6411e5535fedfbff28745 100644
--- a/src/images/SkImageDecoder_libgif.cpp
+++ b/src/images/SkImageDecoder_libgif.cpp
@@ -417,6 +417,7 @@ bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
                 GifInterlaceIter iter(innerHeight);
                 for (int y = 0; y < innerHeight; y++) {
                     if (DGifGetLine(gif, scanline, innerWidth) == GIF_ERROR) {
+#ifdef SK_DECODE_PARTIAL_IMAGES
                         gif_warning(*bm, "interlace DGifGetLine");
                         memset(scanline, fillIndex, innerWidth);
                         for (; y < innerHeight; y++) {
@@ -424,6 +425,9 @@ bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
                             iter.next();
                         }
                         return true;
+#else
+                        return error_return(*bm, "interlace DGifGetLine");
+#endif
                     }
                     sampler.sampleInterlaced(scanline, iter.currY());
                     iter.next();
@@ -434,12 +438,16 @@ bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
                 skip_src_rows(gif, scanline, innerWidth, sampler.srcY0());
                 for (int y = 0; y < outHeight; y++) {
                     if (DGifGetLine(gif, scanline, innerWidth) == GIF_ERROR) {
+#ifdef SK_DECODE_PARTIAL_IMAGES
                         gif_warning(*bm, "DGifGetLine");
                         memset(scanline, fillIndex, innerWidth);
                         for (; y < outHeight; y++) {
                             sampler.next(scanline);
                         }
                         return true;
+#else
+                        return error_return(*bm, "DGifGetLine");
+#endif
                     }
                     // scanline now contains the raw data. Sample it.
                     sampler.next(scanline);