media: Migrate NewTextTrackCB to repeating callback.

This is a repeating callback because it's run from a loop:
* https://cs.chromium.org/chromium/src/media/filters/source_buffer_state.cc?rcl=fd1f7cd492a3db415e007ab24b6ff266fddb43d8&l=773

However, most likely this parameter is not used at all:
* https://crbug.com/1057572

This is part of the base::Callback migration.

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

Bug: 1007805
Change-Id: I5b5d4818ebdfbcad7356f801e2e656b3116494f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2083014
Commit-Queue: Jose Lopes <jabolopes@google.com>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746790}

media/filters/chunk_demuxer.cc

@@ -10,6 +10,7 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/macros.h"
@@ -659,8 +660,6 @@ ChunkDemuxer::Status ChunkDemuxer::AddId(const std::string& id,
                               base::Unretained(this), id),
           media_log_);
 
-  SourceBufferState::NewTextTrackCB new_text_track_cb;
-
   // TODO(wolenetz): Change these to DCHECKs or switch to returning
   // kReachedIdLimit once less verification in release build is needed. See
   // https://crbug.com/786975.
@@ -673,7 +672,7 @@ ChunkDemuxer::Status ChunkDemuxer::AddId(const std::string& id,
   source_state->Init(base::BindOnce(&ChunkDemuxer::OnSourceInitDone,
                                     base::Unretained(this), id),
                      ExpectedCodecs(content_type, codecs),
-                     encrypted_media_init_data_cb_, new_text_track_cb);
+                     encrypted_media_init_data_cb_, base::NullCallback());
 
   // TODO(wolenetz): Change to DCHECKs once less verification in release build
   // is needed. See https://crbug.com/786975.

media/filters/source_buffer_state.cc

@@ -150,11 +150,11 @@ void SourceBufferState::Init(
     StreamParser::InitCB init_cb,
     const std::string& expected_codecs,
     const StreamParser::EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
-    const NewTextTrackCB& new_text_track_cb) {
+    NewTextTrackCB new_text_track_cb) {
   DCHECK_EQ(state_, UNINITIALIZED);
   init_cb_ = std::move(init_cb);
   encrypted_media_init_data_cb_ = encrypted_media_init_data_cb;
-  new_text_track_cb_ = new_text_track_cb;
+  new_text_track_cb_ = std::move(new_text_track_cb);
   state_ = PENDING_PARSER_CONFIG;
   InitializeParser(expected_codecs);
 }

media/filters/source_buffer_state.h

@@ -34,8 +34,8 @@ class MEDIA_EXPORT SourceBufferState {
   using CreateDemuxerStreamCB =
       base::RepeatingCallback<ChunkDemuxerStream*(DemuxerStream::Type)>;
 
-  typedef base::Callback<void(ChunkDemuxerStream*, const TextTrackConfig&)>
-      NewTextTrackCB;
+  using NewTextTrackCB = base::RepeatingCallback<void(ChunkDemuxerStream*,
+                                                      const TextTrackConfig&)>;
 
   SourceBufferState(std::unique_ptr<StreamParser> stream_parser,
                     std::unique_ptr<FrameProcessor> frame_processor,
@@ -48,7 +48,7 @@ class MEDIA_EXPORT SourceBufferState {
             const std::string& expected_codecs,
             const StreamParser::EncryptedMediaInitDataCB&
                 encrypted_media_init_data_cb,
-            const NewTextTrackCB& new_text_track_cb);
+            NewTextTrackCB new_text_track_cb);
 
   // Reconfigures this source buffer to use |new_stream_parser|. Caller must
   // first ensure that ResetParserState() was done to flush any pending frames