Handle audio device changes on Windows.

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 "media/base/channel_layout.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 struct MEDIA_EXPORT AudioInputBufferParameters {
   double volume;
   uint32 size;
 };
 
 // Use a struct-in-struct approach to ensure that we can calculate the required
 // size as sizeof(AudioInputBufferParameters) + #(bytes in audio buffer) without
 // using packing.
 struct MEDIA_EXPORT AudioInputBuffer {
   AudioInputBufferParameters params;
   int8 audio[1];
 };
 
 class MEDIA_EXPORT AudioParameters {
  public:
-  // Compare is useful when AudioParameters is used as a key in std::map.
-  class MEDIA_EXPORT Compare {
-   public:
-    bool operator()(const AudioParameters& a, const AudioParameters& b) const;
-  };
-
   enum Format {
     AUDIO_PCM_LINEAR = 0,     // PCM is 'raw' amplitude samples.
     AUDIO_PCM_LOW_LATENCY,    // Linear PCM, low latency requested.
     AUDIO_FAKE,               // Creates a fake AudioOutputStream object.
     AUDIO_LAST_FORMAT         // Only used for validation of format.
   };
 
   enum {
     // Telephone quality sample rate, mostly for speech-only audio.
     kTelephoneSampleRate = 8000,
@@ skipping 33 matching lines @@
   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|.
 };
 
+// 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.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_