libwebp: cherry-pick lossless incremental decoding fix

third_party/libwebp/dec/vp8l_dec.c

 // Copyright 2012 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // main entry for the decoder
@@ skipping 1072 matching lines @@
       htree_group = GetHtreeGroupForPos(hdr, col, row);
     }
     assert(htree_group != NULL);
     if (htree_group->is_trivial_code) {
       *src = htree_group->literal_arb;
       goto AdvanceByOne;
     }
     VP8LFillBitWindow(br);
     if (htree_group->use_packed_table) {
       code = ReadPackedSymbols(htree_group, br, src);
+      if (br->eos_) break;
       if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne;
     } else {
       code = ReadSymbol(htree_group->htrees[GREEN], br);
     }
     if (br->eos_) break;  // early out
     if (code < NUM_LITERAL_CODES) {  // Literal
       if (htree_group->is_trivial_literal) {
         *src = htree_group->literal_arb | (code << 8);
       } else {
         int red, blue, alpha;
@@ skipping 559 matching lines @@
   params->last_y = dec->last_out_row_;
   return 1;
 
  Err:
   VP8LClear(dec);
   assert(dec->status_ != VP8_STATUS_OK);
   return 0;
 }
 
 //------------------------------------------------------------------------------