# HG changeset patch
# User Timothy Nikkel <tnikkel@gmail.com>
# Date 1678835815 0
# Node ID 53b805c752ff23080e100eda2b3b4280d4370b2e
# Parent  8fcdaf8d685d5903b127e041feb1716637b6008f
Bug 1819244. Cherry pic webp commit fix. r=aosmond, a=dsmith

https://github.com/webmproject/libwebp/commit/a486d800b60d0af4cc0836bf7ed8f21e12974129

Differential Revision: https://phabricator.services.mozilla.com/D171814

diff --git a/media/libwebp/src/enc/alpha_enc.c b/media/libwebp/src/enc/alpha_enc.c
--- a/src/enc/alpha_enc.c
+++ b/src/enc/alpha_enc.c
@@ -8,16 +8,17 @@
 // -----------------------------------------------------------------------------
 //
 // Alpha-plane compression.
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <assert.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "src/enc/vp8i_enc.h"
 #include "src/dsp/dsp.h"
 #include "src/utils/filters_utils.h"
 #include "src/utils/quant_levels_utils.h"
 #include "src/utils/utils.h"
 #include "src/webp/format_constants.h"
 
@@ -143,31 +144,32 @@ static int EncodeAlphaInternal(const uin
       output_size = VP8LBitWriterNumBytes(&tmp_bw);
       if (output_size > data_size) {
         // compressed size is larger than source! Revert to uncompressed mode.
         method = ALPHA_NO_COMPRESSION;
         VP8LBitWriterWipeOut(&tmp_bw);
       }
     } else {
       VP8LBitWriterWipeOut(&tmp_bw);
+      memset(&result->bw, 0, sizeof(result->bw));
       return 0;
     }
   }
 
   if (method == ALPHA_NO_COMPRESSION) {
     output = alpha_src;
     output_size = data_size;
     ok = 1;
   }
 
   // Emit final result.
   header = method | (filter << 2);
   if (reduce_levels) header |= ALPHA_PREPROCESSED_LEVELS << 4;
 
-  VP8BitWriterInit(&result->bw, ALPHA_HEADER_LEN + output_size);
+  if (!VP8BitWriterInit(&result->bw, ALPHA_HEADER_LEN + output_size)) ok = 0;
   ok = ok && VP8BitWriterAppend(&result->bw, &header, ALPHA_HEADER_LEN);
   ok = ok && VP8BitWriterAppend(&result->bw, output, output_size);
 
   if (method != ALPHA_NO_COMPRESSION) {
     VP8LBitWriterWipeOut(&tmp_bw);
   }
   ok = ok && !result->bw.error_;
   result->score = VP8BitWriterSize(&result->bw);