Switch audio synchronization from sleep() based to select() based.

media/audio/audio_output_controller.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_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/atomic_ref_count.h"
 #include "base/callback.h"
 #include "base/cancelable_callback.h"
@@ skipping 73 matching lines @@
   // now that it can handle synchronized I/O.
   class SyncReader {
    public:
     virtual ~SyncReader() {}
 
     // Notify the synchronous reader the number of bytes in the
     // AudioOutputController not yet played. This is used by SyncReader to
     // prepare more data and perform synchronization.
     virtual void UpdatePendingBytes(uint32 bytes) = 0;
 
-    // Attempt to completely fill |dest|, return the actual number of frames
-    // that could be read.  |source| may optionally be provided for input data.
-    // If |block| is specified, the Read() will block until data is available
-    // or a timeout is reached.
-    virtual int Read(bool block, const AudioBus* source, AudioBus* dest) = 0;
+    // Attempts to completely fill |dest|, zeroing |dest| if the request can not
+    // be fulfilled (due to timeout).  |source| may optionally be provided for
+    // input data.
+    virtual void Read(const AudioBus* source, AudioBus* dest) = 0;
 
     // Close this synchronous reader.
     virtual void Close() = 0;
   };
 
   // Factory method for creating an AudioOutputController.
   // This also creates and opens an AudioOutputStream on the audio manager
   // thread, and if this is successful, the |event_handler| will receive an
   // OnCreated() call from the same audio manager thread.  |audio_manager| must
   // outlive AudioOutputController.
@@ skipping 143 matching lines @@
   // When starting stream we wait for data to become available.
   // Number of times left.
   int number_polling_attempts_left_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_