Remove "high"-latency audio code path

media/audio/audio_output_controller.h

Index: media/audio/audio_output_controller.h
diff --git a/media/audio/audio_output_controller.h b/media/audio/audio_output_controller.h
index f6e5722cd4d1a91b7e1f9e50736aa34b652baf24..42f9fc2c4cebfb27c7e7fabc94b7bcc27c7351a9 100644
--- a/media/audio/audio_output_controller.h
+++ b/media/audio/audio_output_controller.h
@@ -30,9 +30,7 @@ class MessageLoop;
 // All the public methods of AudioOutputController are non-blocking.
 // The actual operations are performed on the audio thread.
 //
-// Here is a state diagram for the AudioOutputController for default low
-// latency mode; in normal latency mode there is no "starting" or "paused when
-// starting" states, "created" immediately switches to "playing":
+// Here is a state diagram for the AudioOutputController:
 //
 //             .----------------------->  [ Closed / Error ]  <------.
 //             |                                   ^                 |
@@ -48,15 +46,9 @@ class MessageLoop;
 //
 // * Initial state
 //
-// There are two modes of buffering operations supported by this class.
-//
-// Regular latency mode:
-//   In this mode we receive signals from AudioOutputController and then we
-//   enqueue data into it.
-//
-// Low latency mode:
-//   In this mode a DataSource object is given to the AudioOutputController
-//   and AudioOutputController reads from it synchronously.
+// The AudioOutputStream can request data from the AudioOutputController via the
+// AudioSourceCallback interface. AudioOutputController uses the SyncReader

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

I think we call the same interface on the render side AudioSink and not Source.
Might be a bit confusing. I feel that Sink is the the correct term since the
interface specifies a data consumption. 

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Yeah, I am planning to go through and rename some of these interfaces and
methods to make things more uniform. Probably in a follow-up CL?

For now, I'll leave this comment as-is if that's okay.

[henrika (OOO until Aug 14), 2012/02/01 13:11:29]

Sounds fine.

+// passed to it via construction to synchronously fulfill this read request.
 //
 // The audio thread itself is owned by the AudioManager that the
 // AudioOutputController holds a reference to.  When performing tasks on the
@@ -89,12 +81,6 @@ class MEDIA_EXPORT AudioOutputController
     virtual void OnPlaying(AudioOutputController* controller) = 0;
     virtual void OnPaused(AudioOutputController* controller) = 0;
     virtual void OnError(AudioOutputController* controller, int error_code) = 0;
-
-    // Audio controller asks for more data.
-    // |pending_bytes| is the number of bytes still on the controller.
-    // |timestamp| is then time when |pending_bytes| is recorded.
-    virtual void OnMoreData(AudioOutputController* controller,
-                            AudioBuffersState buffers_state) = 0;
   };
 
   // A synchronous reader interface used by AudioOutputController for
@@ -131,15 +117,6 @@ class MEDIA_EXPORT AudioOutputController
       AudioManager* audio_manager,
       EventHandler* event_handler,
       const AudioParameters& params,
-      // Soft limit for buffer capacity in this controller. This parameter
-      // is used only in regular latency mode.
-      uint32 buffer_capacity);
-
-  // Factory method for creating a low latency audio stream.
-  static scoped_refptr<AudioOutputController> CreateLowLatency(
-      AudioManager* audio_manager,
-      EventHandler* event_handler,
-      const AudioParameters& params,
       // External synchronous reader for audio controller.
       SyncReader* sync_reader);
 
@@ -167,13 +144,6 @@ class MEDIA_EXPORT AudioOutputController
   // Sets the volume of the audio output stream.
   void SetVolume(double volume);
 
-  // Enqueue audio |data| into the controller. This method is used only in
-  // the regular latency mode and it is illegal to call this method when
-  // SyncReader is present.
-  void EnqueueData(const uint8* data, uint32 size);
-
-  bool LowLatencyMode() const { return sync_reader_ != NULL; }
-
   ///////////////////////////////////////////////////////////////////////////
   // AudioSourceCallback methods.
   virtual uint32 OnMoreData(AudioOutputStream* stream,
@@ -206,7 +176,7 @@ class MEDIA_EXPORT AudioOutputController
 
   AudioOutputController(AudioManager* audio_manager,
                         EventHandler* handler,
-                        uint32 capacity, SyncReader* sync_reader);
+                        SyncReader* sync_reader);
 
   // The following methods are executed on the audio controller thread.
   void DoCreate(const AudioParameters& params);
@@ -218,9 +188,6 @@ class MEDIA_EXPORT AudioOutputController
   void DoSetVolume(double volume);
   void DoReportError(int code);
 
-  // Helper method to submit a OnMoreData() call to the event handler.
-  void SubmitOnMoreData_Locked();
-
   // Helper method that starts physical stream.
   void StartStream();
 
@@ -241,15 +208,10 @@ class MEDIA_EXPORT AudioOutputController
   // is not required for reading on the audio controller thread.
   State state_;
 
-  AudioBuffersState buffers_state_;
-
-  // The |lock_| must be acquired whenever we access |buffer_|.
+  // The |lock_| must be acquired whenever we access |state_| from a thread
+  // other than the audio controller thread.

[henrika (OOO until Aug 14), 2012/01/29 20:54:00]

Rename to audio-manager thread?

[vrk (LEFT CHROMIUM), 2012/01/31 23:53:08]

Done.

   base::Lock lock_;
 
-  media::SeekableBuffer buffer_;
-
-  bool pending_request_;
-
   // SyncReader is used only in low latency mode for synchronous reading.
   SyncReader* sync_reader_;