Convert base::Bind in media::WebSourceBufferImpl

BindRepeating is correct because SetTracksWatcher expects a
media::MediaTracksUpdatedCB which is a base::RepeatingCallback. The
callback is called whenever the media track configuration has been
updated, which is expected to occur more than once.

BUG=1102651

Change-Id: Ibc60aec4cbd7692dfd94a74429d718d38171bc5f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2284226
Auto-Submit: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786517}

media/blink/websourcebuffer_impl.cc

@@ -70,8 +70,8 @@ WebSourceBufferImpl::WebSourceBufferImpl(const std::string& id,
       append_window_end_(kInfiniteDuration) {
   DCHECK(demuxer_);
   demuxer_->SetTracksWatcher(
-      id, base::Bind(&WebSourceBufferImpl::InitSegmentReceived,
-                     base::Unretained(this)));
+      id, base::BindRepeating(&WebSourceBufferImpl::InitSegmentReceived,
+                              base::Unretained(this)));
   demuxer_->SetParseWarningCallback(
       id, base::BindRepeating(&WebSourceBufferImpl::NotifyParseWarning,
                               base::Unretained(this)));