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

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 <stdint.h>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/time/time.h"
 #include "media/audio/point.h"
 #include "media/base/audio_bus.h"
 #include "media/base/channel_layout.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // 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. Also align AudioInputBufferParameters instead of in
-// AudioInputBuffer to be able to calculate size like so. Use a macro for the
-// alignment value that's the same as AudioBus::kChannelAlignment, since MSVC
-// doesn't accept the latter to be used.
+// size as sizeof(Audio{Input,Output}BufferParameters) + #(bytes in audio
+// buffer) without using packing. Also align Audio{Input,Output}BufferParameters
+// instead of in Audio{Input,Output}Buffer to be able to calculate size like so.
+// Use a macro for the alignment value that's the same as
+// AudioBus::kChannelAlignment, since MSVC doesn't accept the latter to be used.
 #if defined(OS_WIN)
 #pragma warning(push)
 #pragma warning(disable: 4324)  // Disable warning for added padding.
 #endif
 #define PARAMETERS_ALIGNMENT 16
 static_assert(AudioBus::kChannelAlignment == PARAMETERS_ALIGNMENT,
-              "AudioInputBufferParameters alignment not same as AudioBus");
+              "Audio buffer parameters struct alignment not same as AudioBus");
 struct MEDIA_EXPORT ALIGNAS(PARAMETERS_ALIGNMENT) AudioInputBufferParameters {
   double volume;
-  uint32 size;
+  uint32_t size;
   uint32_t hardware_delay_bytes;
   uint32_t id;
   bool key_pressed;
 };
+struct MEDIA_EXPORT ALIGNAS(PARAMETERS_ALIGNMENT) AudioOutputBufferParameters {
+  uint32_t frames_skipped;
+};
 #undef PARAMETERS_ALIGNMENT
 #if defined(OS_WIN)
 #pragma warning(pop)
 #endif
 
 static_assert(sizeof(AudioInputBufferParameters) %
                       AudioBus::kChannelAlignment ==
                   0,
               "AudioInputBufferParameters not aligned");
+static_assert(sizeof(AudioOutputBufferParameters) %
+                      AudioBus::kChannelAlignment ==
+                  0,
+              "AudioOutputBufferParameters not aligned");
 
 struct MEDIA_EXPORT AudioInputBuffer {
   AudioInputBufferParameters params;
   int8 audio[1];
 };
+struct MEDIA_EXPORT AudioOutputBuffer {
+  AudioOutputBufferParameters params;
+  int8 audio[1];
+};
 
 class MEDIA_EXPORT AudioParameters {
  public:
   // TODO(miu): Rename this enum to something that correctly reflects its
   // semantics, such as "TransportScheme."
   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_FORMAT_LAST = AUDIO_FAKE,  // Only used for validation of format.
@@ skipping 128 matching lines @@
   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_