Use macro for AudioInputBufferParameters alignment.

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/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.
+// 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.
 #if defined(OS_WIN)
 #pragma warning(push)
 #pragma warning(disable: 4324)  // Disable warning for added padding.
 #endif
-struct MEDIA_EXPORT ALIGNAS(16) AudioInputBufferParameters {
+#define PARAMETERS_ALIGNMENT 16
+COMPILE_ASSERT(AudioBus::kChannelAlignment == PARAMETERS_ALIGNMENT,
+               AudioInputBufferParameters_alignment_not_same_as_AudioBus);
+struct MEDIA_EXPORT ALIGNAS(PARAMETERS_ALIGNMENT) AudioInputBufferParameters {
   double volume;
   uint32 size;
   uint32_t hardware_delay_bytes;
   uint32_t id;
   bool key_pressed;
 };
+#undef PARAMETERS_ALIGNMENT
 #if defined(OS_WIN)
 #pragma warning(pop)
 #endif
 
 COMPILE_ASSERT(
     sizeof(AudioInputBufferParameters) % AudioBus::kChannelAlignment == 0,
     AudioInputBufferParameters_not_aligned);
 
 struct MEDIA_EXPORT AudioInputBuffer {
   AudioInputBufferParameters params;
@@ skipping 98 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_