Migrate media tracks updated callback.

This callback is called in:
  https://cs.chromium.org/chromium/src/media/filters/source_buffer_state.cc?rcl=aa249ef6fe237699a94759d51dfa5f3cd2b55966&l=852
which is in the context of the method:
  https://cs.chromium.org/chromium/src/media/filters/source_buffer_state.cc?rcl=aa249ef6fe237699a94759d51dfa5f3cd2b55966&l=590
which is bound repeating, so it can be called multiple times:
  https://cs.chromium.org/chromium/src/media/filters/source_buffer_state.cc?rcl=bfd9a7897bf5085cdab7041c8df7077b35156b97&l=576

This is part of the base::Callback migration.

Context: https://cs.chromium.org/chromium/src/docs/callback.md?rcl=9fcc3764aea8f97e9f6de4a9ee61d554e67edcda&l=40

Bug: 714018
Change-Id: I180addc28f5d7034d9bb7c46833cc34ed195e04e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2036099
Auto-Submit: Jose Lopes <jabolopes@google.com>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Jose Lopes <jabolopes@google.com>
Cr-Commit-Position: refs/heads/master@{#743045}

media/base/demuxer.h

@@ -64,7 +64,7 @@ class MEDIA_EXPORT Demuxer : public MediaResource {
   // (e.g. the initial stream metadata has been parsed successfully, or a new
   // init segment has been parsed successfully in MSE case).
   using MediaTracksUpdatedCB =
-      base::Callback<void(std::unique_ptr<MediaTracks>)>;
+      base::RepeatingCallback<void(std::unique_ptr<MediaTracks>)>;
 
   // Called once the demuxer has finished enabling or disabling tracks. The type
   // argument is required because the vector may be empty.

media/blink/webmediaplayer_impl.cc

@@ -2726,7 +2726,7 @@ void WebMediaPlayerImpl::StartPipeline() {
 
 #if BUILDFLAG(ENABLE_FFMPEG)
     Demuxer::MediaTracksUpdatedCB media_tracks_updated_cb =
-        BindToCurrentLoop(base::Bind(
+        BindToCurrentLoop(base::BindRepeating(
             &WebMediaPlayerImpl::OnFFmpegMediaTracksUpdated, weak_this_));
 
     demuxer_ = std::make_unique<FFmpegDemuxer>(

media/filters/ffmpeg_demuxer.cc

@@ -914,7 +914,7 @@ FFmpegDemuxer::FFmpegDemuxer(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     DataSource* data_source,
     const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
-    const MediaTracksUpdatedCB& media_tracks_updated_cb,
+    MediaTracksUpdatedCB media_tracks_updated_cb,
     MediaLog* media_log,
     bool is_local_file)
     : task_runner_(task_runner),
@@ -927,7 +927,7 @@ FFmpegDemuxer::FFmpegDemuxer(
       data_source_(data_source),
       media_log_(media_log),
       encrypted_media_init_data_cb_(encrypted_media_init_data_cb),
-      media_tracks_updated_cb_(media_tracks_updated_cb),
+      media_tracks_updated_cb_(std::move(media_tracks_updated_cb)),
       is_local_file_(is_local_file) {
   DCHECK(task_runner_.get());
   DCHECK(data_source_);

media/filters/ffmpeg_demuxer.h

@@ -214,7 +214,7 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   FFmpegDemuxer(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
                 DataSource* data_source,
                 const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
-                const MediaTracksUpdatedCB& media_tracks_updated_cb,
+                MediaTracksUpdatedCB media_tracks_updated_cb,
                 MediaLog* media_log,
                 bool is_local_file);
   ~FFmpegDemuxer() override;