Use aligned buffer in the audio mixer.

media/audio/audio_output_mixer.cc

Index: media/audio/audio_output_mixer.cc
===================================================================
--- media/audio/audio_output_mixer.cc	(revision 140416)
+++ media/audio/audio_output_mixer.cc	(working copy)
@@ -20,14 +20,13 @@
                                    const AudioParameters& params,
                                    const base::TimeDelta& close_delay)
     : AudioOutputDispatcher(audio_manager, params),
+      mixer_data_(new DecoderBuffer(params_.GetBytesPerBuffer())),

[scherkus (not reviewing), 2012/06/05 16:37:43]

I'm not convinced we should be using DecoderBuffer as a general purpose aligned
memory allocator.

Would src/base/memory/aligned_memory.h work here instead?

       ALLOW_THIS_IN_INITIALIZER_LIST(weak_this_(this)),
       close_timer_(FROM_HERE,
                    close_delay,
                    weak_this_.GetWeakPtr(),
                    &AudioOutputMixer::ClosePhysicalStream),
       pending_bytes_(0) {
-  // TODO(enal): align data.
-  mixer_data_.reset(new uint8[params_.GetBytesPerBuffer()]);
 }
 
 AudioOutputMixer::~AudioOutputMixer() {
@@ -208,7 +207,7 @@
       if (actual_size < max_size)
         memset(dest + actual_size, 0, max_size - actual_size);
       first_stream = false;
-      actual_dest = mixer_data_.get();
+      actual_dest = mixer_data_->GetWritableData();
       actual_total_size = actual_size;
     } else {
       media::MixStreams(dest,