Revert 259154 "Remove HasAudio(), HasVideo(), GetInitialNaturalS..."

trunk/src/media/base/pipeline.h

Index: trunk/src/media/base/pipeline.h
===================================================================
--- trunk/src/media/base/pipeline.h	(revision 259158)
+++ trunk/src/media/base/pipeline.h	(working copy)
@@ -34,17 +34,6 @@
 class TextTrackConfig;
 class VideoRenderer;
 
-// Metadata describing a pipeline once it has been initialized.
-struct PipelineMetadata {
-  PipelineMetadata() : has_audio(false), has_video(false) {}
-
-  bool has_audio;
-  bool has_video;
-  gfx::Size natural_size;
-};
-
-typedef base::Callback<void(PipelineMetadata)> PipelineMetadataCB;
-
 // Pipeline runs the media pipeline.  Filters are created and called on the
 // task runner injected into this object. Pipeline works like a state
 // machine to perform asynchronous initialization, pausing, seeking and playing.
@@ -78,6 +67,21 @@
 // "Stopped" state.
 class MEDIA_EXPORT Pipeline : public DemuxerHost {
  public:
+  // Buffering states the pipeline transitions between during playback.
+  // kHaveMetadata:
+  //   Indicates that the following things are known:
+  //   content duration, container video size, start time, and whether the
+  //   content has audio and/or video in supported formats.
+  // kPrerollCompleted:
+  //   All renderers have buffered enough data to satisfy preroll and are ready
+  //   to start playback.
+  enum BufferingState {
+    kHaveMetadata,
+    kPrerollCompleted,
+  };
+
+  typedef base::Callback<void(BufferingState)> BufferingStateCB;
+
   // Constructs a media pipeline that will execute on |task_runner|.
   Pipeline(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
            MediaLog* media_log);
@@ -93,23 +97,18 @@
   // The following permanent callbacks will be executed as follows up until
   // Stop() has completed:
   //   |ended_cb| will be executed whenever the media reaches the end.
-  //   |error_cb| will be executed whenever an error occurs but hasn't been
-  //              reported already through another callback.
-  //   |metadata_cb| will be executed when the content duration, container video
-  //                 size, start time, and whether the content has audio and/or
-  //                 video in supported formats are known.
-  //   |preroll_completed_cb| will be executed when all renderers have buffered
-  //                          enough data to satisfy preroll and are ready to
-  //                          start playback.
-  //   |duration_change_cb| optional callback that will be executed whenever the
+  //   |error_cb| will be executed whenever an error occurs but hasn't
+  //              been reported already through another callback.
+  //   |buffering_state_cb| Optional callback that will be executed whenever the
+  //                    pipeline's buffering state changes.
+  //   |duration_change_cb| Optional callback that will be executed whenever the
   //                        presentation duration changes.
   // It is an error to call this method after the pipeline has already started.
   void Start(scoped_ptr<FilterCollection> filter_collection,
              const base::Closure& ended_cb,
              const PipelineStatusCB& error_cb,
              const PipelineStatusCB& seek_cb,
-             const PipelineMetadataCB& metadata_cb,
-             const base::Closure& preroll_completed_cb,
+             const BufferingStateCB& buffering_state_cb,
              const base::Closure& duration_change_cb);
 
   // Asynchronously stops the pipeline, executing |stop_cb| when the pipeline
@@ -135,6 +134,12 @@
   // the pipeline.
   bool IsRunning() const;
 
+  // Returns true if the media has audio.
+  bool HasAudio() const;
+
+  // Returns true if the media has video.
+  bool HasVideo() const;
+
   // Gets the current playback rate of the pipeline.  When the pipeline is
   // started, the playback rate will be 0.0f.  A rate of 1.0f indicates
   // that the pipeline is rendering the media at the standard rate.  Valid
@@ -173,6 +178,10 @@
   // determined or can not be determined, this value is 0.
   int64 GetTotalBytes() const;
 
+  // Get the video's initial natural size as reported by the container. Note
+  // that the natural size can change during playback.
+  gfx::Size GetInitialNaturalSize() const;
+
   // Return true if loading progress has been made since the last time this
   // method was called.
   bool DidLoadingProgress() const;
@@ -253,7 +262,12 @@
   // The following "task" methods correspond to the public methods, but these
   // methods are run as the result of posting a task to the Pipeline's
   // task runner.
-  void StartTask();
+  void StartTask(scoped_ptr<FilterCollection> filter_collection,
+                 const base::Closure& ended_cb,
+                 const PipelineStatusCB& error_cb,
+                 const PipelineStatusCB& seek_cb,
+                 const BufferingStateCB& buffering_state_cb,
+                 const base::Closure& duration_change_cb);
 
   // Stops and destroys all filters, placing the pipeline in the kStopped state.
   void StopTask(const base::Closure& stop_cb);
@@ -356,6 +370,9 @@
   // Total size of the media.  Set by filters.
   int64 total_bytes_;
 
+  // The initial natural size of the video as reported by the container.
+  gfx::Size initial_natural_size_;
+
   // Current volume level (from 0.0f to 1.0f).  This value is set immediately
   // via SetVolume() and a task is dispatched on the task runner to notify the
   // filters.
@@ -385,6 +402,13 @@
   // reset the pipeline state, and restore this to PIPELINE_OK.
   PipelineStatus status_;
 
+  // Whether the media contains rendered audio or video streams.
+  // TODO(fischman,scherkus): replace these with checks for
+  // {audio,video}_decoder_ once extraction of {Audio,Video}Decoder from the
+  // Filter heirarchy is done.
+  bool has_audio_;
+  bool has_video_;
+
   // The following data members are only accessed by tasks posted to
   // |task_runner_|.
 
@@ -408,8 +432,7 @@
   // Permanent callbacks passed in via Start().
   base::Closure ended_cb_;
   PipelineStatusCB error_cb_;
-  PipelineMetadataCB metadata_cb_;
-  base::Closure preroll_completed_cb_;
+  BufferingStateCB buffering_state_cb_;
   base::Closure duration_change_cb_;
 
   // Contains the demuxer and renderers to use when initializing.