Forward the number of skipped frames by the OS in audio playout.

media/audio/audio_device_thread.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_AUDIO_AUDIO_DEVICE_THREAD_H_
 #define MEDIA_AUDIO_AUDIO_DEVICE_THREAD_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 32 matching lines @@
              int total_segments);
     virtual ~Callback();
 
     // One time initialization for the callback object on the audio thread.
     void InitializeOnAudioThread();
 
     // Derived implementations must call shared_memory_.Map appropriately
     // before Process can be called.
     virtual void MapSharedMemory() = 0;
 
-    // Called whenever we receive notifications about pending data.
-    virtual void Process(uint32 pending_data) = 0;
+    // Called whenever we receive notifications about pending input data.
+    // |frames_skipped| contains the number of frames that has been skipped. The
+    // source can handle this appropriately depending on its type. An ordinary
+    // file playout would ignore this.
+    virtual void Process(uint32_t pending_data, uint32_t frames_skipped) = 0;
 
    protected:
     // Protected so that derived classes can access directly.
     // The variables are 'const' since values are calculated/set in the
     // constructor and must never change.
     const AudioParameters audio_parameters_;
     const int samples_per_ms_;
     const int bytes_per_ms_;
 
     base::SharedMemory shared_memory_;
     const int memory_length_;
     const int total_segments_;
     int segment_length_;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Callback);
   };
 
   AudioDeviceThread();
   ~AudioDeviceThread();
 
   // Starts the audio thread. The thread must not already be running.  If
   // |sychronized_buffers| is set, the browser expects to be notified via the
-  // |socket| every time AudioDeviceThread::Process() completes.
+  // |socket| every time AudioDeviceThread::Process() completes. |input| should
+  // be true for input and false for output. It is used for reading the right
+  // amount of data from the socket.
+  // TODO(grunell): |input| is ugly, but there are plans to re-use a thread for
+  // multiple inputs/outputs (see todo comment above) so we do it this way
+  // meanwhile instead of using separate classes.
   void Start(AudioDeviceThread::Callback* callback,
              base::SyncSocket::Handle socket,
              const char* thread_name,
-             bool synchronized_buffers);
+             bool synchronized_buffers,
+             bool input);
 
   // This tells the audio thread to stop and clean up the data.
   // The method can stop the thread synchronously or asynchronously.
   // In the latter case, the thread will still be running after Stop()
   // returns, but the callback pointer is cleared so no further callbacks will
   // be made (IOW after Stop() returns, it is safe to delete the callback).
   // The |loop_for_join| parameter is required for asynchronous operation
   // in order to join the worker thread and close the thread handle later via a
   // posted task.
   // If set to NULL, function will wait for the thread to exit before returning.
@@ skipping 14 matching lines @@
 
   base::Lock thread_lock_;
   scoped_refptr<AudioDeviceThread::Thread> thread_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioDeviceThread);
 };
 
 }  // namespace media.
 
 #endif  // MEDIA_AUDIO_AUDIO_DEVICE_THREAD_H_