Render inband text tracks in the media pipeline

media/base/demuxer.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_DEMUXER_H_
 #define MEDIA_BASE_DEMUXER_H_
 
 #include <vector>
 
 #include "base/time/time.h"
 #include "media/base/data_source.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/media_export.h"
 #include "media/base/pipeline_status.h"
 
 namespace media {
 
+class TextTrackConfig;
+
 class MEDIA_EXPORT DemuxerHost : public DataSourceHost {
  public:
   // Sets the duration of the media in microseconds.
   // Duration may be kInfiniteDuration() if the duration is not known.
   virtual void SetDuration(base::TimeDelta duration) = 0;
 
   // Stops execution of the pipeline due to a fatal error.  Do not call this
   // method with PIPELINE_OK.
   virtual void OnDemuxerError(PipelineStatus error) = 0;
 
+  // Add |text_stream| to the collection managed by the text renderer.
+  virtual void AddTextStream(DemuxerStream* text_stream,
+                             const TextTrackConfig& config) = 0;
+
+  // Remove |text_stream| from the presentation.
+  virtual void RemoveTextStream(DemuxerStream* text_stream) = 0;
+
  protected:
   virtual ~DemuxerHost();
 };
 
 class MEDIA_EXPORT Demuxer {
  public:
   // A new potentially encrypted stream has been parsed.
   // First parameter - The type of initialization data.
   // Second parameter - The initialization data associated with the stream.
   typedef base::Callback<void(const std::string& type,
                               const std::vector<uint8>& init_data)> NeedKeyCB;
 
   Demuxer();
   virtual ~Demuxer();
 
   // Completes initialization of the demuxer.
   //
   // The demuxer does not own |host| as it is guaranteed to outlive the
   // lifetime of the demuxer. Don't delete it!
   virtual void Initialize(DemuxerHost* host,
-                          const PipelineStatusCB& status_cb) = 0;
+                          const PipelineStatusCB& status_cb,
+                          bool enable_text_tracks) = 0;
 
   // Carry out any actions required to seek to the given time, executing the
   // callback upon completion.
   virtual void Seek(base::TimeDelta time,
                     const PipelineStatusCB& status_cb) = 0;
 
   // Starts stopping this demuxer, executing the callback upon completion.
   //
   // After the callback completes the demuxer may be destroyed. It is illegal to
   // call any method (including Stop()) after a demuxer has stopped.
   virtual void Stop(const base::Closure& callback) = 0;
 
   // This method is called from the pipeline when the audio renderer
   // is disabled. Demuxers can ignore the notification if they do not
   // need to react to this event.
   //
   // TODO(acolwell): Change to generic DisableStream(DemuxerStream::Type).
   // TODO(scherkus): this might not be needed http://crbug.com/234708
   virtual void OnAudioRendererDisabled() = 0;
 
-  // Returns the given stream type, or NULL if that type is not present.
+  // Returns the first stream of the given stream type (which is not allowed
+  // to be DemuxerStream::TEXT), or NULL if that type of stream is not present.
   virtual DemuxerStream* GetStream(DemuxerStream::Type type) = 0;
 
   // Returns the starting time for the media file.
   virtual base::TimeDelta GetStartTime() const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DEMUXER_H_