The bundled ffmpeg in Chromium is newer than the one in Guix.  Patch so
we can build with the new and old ffmpeg versions.

Taken from Gentoo:
https://gitweb.gentoo.org/repo/gentoo.git/tree/www-client/chromium/files/chromium-93-fix-build-with-system-ffmpeg.patch

diff --git a/media/filters/audio_decoder_unittest.cc b/media/filters/audio_decoder_unittest.cc
--- a/media/filters/audio_decoder_unittest.cc
+++ b/media/filters/audio_decoder_unittest.cc
@@ -109,7 +109,11 @@ void SetDiscardPadding(AVPacket* packet,
   }
 
   // If the timestamp is positive, try to use FFmpeg's discard data.
+#if LIBAVUTIL_VERSION_MAJOR < 57
+  int skip_samples_size = 0;
+#else
   size_t skip_samples_size = 0;
+#endif
   const uint32_t* skip_samples_ptr =
       reinterpret_cast<const uint32_t*>(av_packet_get_side_data(
           packet, AV_PKT_DATA_SKIP_SAMPLES, &skip_samples_size));
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -427,11 +427,19 @@ void FFmpegDemuxerStream::EnqueuePacket(
   scoped_refptr<DecoderBuffer> buffer;
 
   if (type() == DemuxerStream::TEXT) {
+#if LIBAVUTIL_VERSION_MAJOR < 57
+    int id_size = 0;
+#else
     size_t id_size = 0;
+#endif
     uint8_t* id_data = av_packet_get_side_data(
         packet.get(), AV_PKT_DATA_WEBVTT_IDENTIFIER, &id_size);
 
+#if LIBAVUTIL_VERSION_MAJOR < 57
+    int settings_size = 0;
+#else
     size_t settings_size = 0;
+#endif
     uint8_t* settings_data = av_packet_get_side_data(
         packet.get(), AV_PKT_DATA_WEBVTT_SETTINGS, &settings_size);
 
@@ -443,7 +451,11 @@ void FFmpegDemuxerStream::EnqueuePacket(
     buffer = DecoderBuffer::CopyFrom(packet->data, packet->size,
                                      side_data.data(), side_data.size());
   } else {
+#if LIBAVUTIL_VERSION_MAJOR < 57
+    int side_data_size = 0;
+#else
     size_t side_data_size = 0;
+#endif
     uint8_t* side_data = av_packet_get_side_data(
         packet.get(), AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL, &side_data_size);
 
@@ -504,7 +516,11 @@ void FFmpegDemuxerStream::EnqueuePacket(
                                        packet->size - data_offset);
     }
 
+#if LIBAVUTIL_VERSION_MAJOR < 57
+    int skip_samples_size = 0;
+#else
     size_t skip_samples_size = 0;
+#endif
     const uint32_t* skip_samples_ptr =
         reinterpret_cast<const uint32_t*>(av_packet_get_side_data(
             packet.get(), AV_PKT_DATA_SKIP_SAMPLES, &skip_samples_size));
9:47 +0100'>2021-12-18</span></td><td><a href='/guix/commit/tests/cran.scm?id=10ceb3e84654e024f14a4b048e7d68492ed9dc7c'>import: cran: Fix description-&gt;package test.</a><span class='msg-avail'>...<span class='msg-tooltip'>This follows up on commit 5cd1019488c44081aaf030fbe8bc357d78daef23.

* tests/cran.scm (description): Include a very long line.
(description-&gt;package): Update the golden description to match the
paragraph filling now performed by BEAUTIFY-DESCRIPTION.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-07-11 00:49:16 +0200'>2021-07-11</span></td><td><a href='/guix/commit/tests/cran.scm?id=aa6921634b4ea9988af0e37bfbb56780c431ef64'>import: cran: Emit new-style package inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (format-inputs): Emit symbols or
'specification-&gt;package' calls.
(maybe-inputs): Wrap in 'list' instead of 'quasiquote'.
* tests/cran.scm ("description-&gt;package"): Adjust accordingly.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-16 23:14:05 +0100'>2020-01-16</span></td><td><a href='/guix/commit/tests/cran.scm?id=cfd1ed84013df85f0e473884ef4038b4bd7120d4'>import: cran: Avoid uses of '@@' in the tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (description-&gt;alist, description-&gt;package): Export.
&lt;top level&gt;: Set! 'listify'.
* tests/cran.scm (description-alist, "description-&gt;package"): Remove use
of '@@' to access the relevant bindings.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-05-13 12:40:20 +0200'>2017-05-13</span></td><td><a href='/guix/commit/tests/cran.scm?id=db427602d8f993ee0025fa68d1af274aa8d69ab9'>import: cran: Robustify cran-package?.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/import/cran.scm (package-&gt;upstream-name): Return #f if url
  start and end index could not be determined.
  (cran-package?): Check if the upstream-name can be extracted from
  given package.
* tests/cran.scm: Add "r-minimal is not a cran package" to make sure that
  r-minimal is not detected as a cran package.

This fixes a failure of guix refresh on r-minimal because no
upsteam-name can be determined from ".../R-version.tar.gz" uri.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2017-03-08 23:42:52 +0100'>2017-03-08</span></td><td><a href='/guix/commit/tests/cran.scm?id=dd420bf3430eb644b93ca224da4c0a3f5db7a42f'>tests: Avoid zero-expression 'begin' form.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/cran.scm ("description-&gt;package"): Add body after the expected
pattern in 'match'.
</span></span></td><td>Ludovic Courtès</td></tr>