Fixes for partial images.

src/images/SkImageDecoder_libgif.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
@@ skipping 399 matching lines @@
                 return error_return(*bm, "Sampler failed to begin.");
             }
 
             // now decode each scanline
             if (gif->Image.Interlace) {
                 // Iterate over the height of the source data. The sampler will
                 // take care of skipping unneeded rows.
                 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++) {
                             sampler.sampleInterlaced(scanline, iter.currY());
                             iter.next();
                         }
                         return true;
+#else
+                        return error_return(*bm, "interlace DGifGetLine");
+#endif
                     }
                     sampler.sampleInterlaced(scanline, iter.currY());
                     iter.next();
                 }
             } else {
                 // easy, non-interlace case
                 const int outHeight = workingBitmap->height();
                 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);
                     if (y < outHeight - 1) {
                         skip_src_rows(gif, scanline, innerWidth, sampler.srcDY() - 1);
                     }
                 }
                 // skip the rest of the rows (if any)
                 int read = (outHeight - 1) * sampler.srcDY() + sampler.srcY0() + 1;
                 SkASSERT(read <= innerHeight);
@@ skipping 74 matching lines @@
 static SkImageDecoder_DecodeReg gReg(sk_libgif_dfactory);
 
 static SkImageDecoder::Format get_format_gif(SkStreamRewindable* stream) {
     if (is_gif(stream)) {
         return SkImageDecoder::kGIF_Format;
     }
     return SkImageDecoder::kUnknown_Format;
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_gif);