Revert of Remove the last piece of deprecated synchronous IO code.

media/audio/audio_parameters.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_PARAMETERS_H_
 #define MEDIA_AUDIO_AUDIO_PARAMETERS_H_
 
 #include "base/basictypes.h"
 #include "base/time/time.h"
 #include "media/base/channel_layout.h"
@@ skipping 40 matching lines @@
     ECHO_CANCELLER = 0x1,
     DUCKING = 0x2,  // Enables ducking if the OS supports it.
     KEYBOARD_MIC = 0x4,
   };
 
   AudioParameters();
   AudioParameters(Format format, ChannelLayout channel_layout,
                   int sample_rate, int bits_per_sample,
                   int frames_per_buffer);
   AudioParameters(Format format, ChannelLayout channel_layout,
+                  int input_channels,
                   int sample_rate, int bits_per_sample,
                   int frames_per_buffer, int effects);
   AudioParameters(Format format, ChannelLayout channel_layout,
-                  int channels, int sample_rate, int bits_per_sample,
+                  int channels, int input_channels,
+                  int sample_rate, int bits_per_sample,
                   int frames_per_buffer, int effects);
 
   void Reset(Format format, ChannelLayout channel_layout,
-             int channels, int sample_rate, int bits_per_sample,
+             int channels, int input_channels,
+             int sample_rate, int bits_per_sample,
              int frames_per_buffer);
 
   // Checks that all values are in the expected range. All limits are specified
   // in media::Limits.
   bool IsValid() const;
 
   // Returns size of audio buffer in bytes.
   int GetBytesPerBuffer() const;
 
   // Returns the number of bytes representing one second of audio.
   int GetBytesPerSecond() const;
 
   // Returns the number of bytes representing a frame of audio.
   int GetBytesPerFrame() const;
 
   // Returns the duration of this buffer as calculated from frames_per_buffer()
   // and sample_rate().
   base::TimeDelta GetBufferDuration() const;
 
   Format format() const { return format_; }
   ChannelLayout channel_layout() const { return channel_layout_; }
   int sample_rate() const { return sample_rate_; }
   int bits_per_sample() const { return bits_per_sample_; }
   int frames_per_buffer() const { return frames_per_buffer_; }
   int channels() const { return channels_; }
+  int input_channels() const { return input_channels_; }
   int effects() const { return effects_; }
 
   // Comparison with other AudioParams.
   bool operator==(const AudioParameters& other) const {
     return format_ == other.format() &&
            sample_rate_ == other.sample_rate() &&
            channel_layout_ == other.channel_layout() &&
            channels_ == other.channels() &&
+           input_channels_ == other.input_channels() &&
            bits_per_sample_ == other.bits_per_sample() &&
            frames_per_buffer_ == other.frames_per_buffer() &&
            effects_ == other.effects();
   }
 
  private:
   // These members are mutable to support entire struct assignment. They should
   // not be mutated individually.
   Format format_;                 // Format of the stream.
   ChannelLayout channel_layout_;  // Order of surround sound channels.
   int sample_rate_;               // Sampling frequency/rate.
   int bits_per_sample_;           // Number of bits per sample.
   int frames_per_buffer_;         // Number of frames in a buffer.
 
   int channels_;                  // Number of channels. Value set based on
                                   // |channel_layout|.
+  int input_channels_;            // Optional number of input channels.
+                                  // Normally 0, but can be set to specify
+                                  // synchronized I/O.
   int effects_;                   // Bitmask using PlatformEffectsMask.
 };
 
 // Comparison is useful when AudioParameters is used with std structures.
 inline bool operator<(const AudioParameters& a, const AudioParameters& b) {
   if (a.format() != b.format())
     return a.format() < b.format();
   if (a.channels() != b.channels())
     return a.channels() < b.channels();
+  if (a.input_channels() != b.input_channels())
+    return a.input_channels() < b.input_channels();
   if (a.sample_rate() != b.sample_rate())
     return a.sample_rate() < b.sample_rate();
   if (a.bits_per_sample() != b.bits_per_sample())
     return a.bits_per_sample() < b.bits_per_sample();
   return a.frames_per_buffer() < b.frames_per_buffer();
 }
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_PARAMETERS_H_