Move media/audio files into media namespace

media/audio/linux/alsa_wrapper.cc

Index: media/audio/linux/alsa_wrapper.cc
diff --git a/media/audio/linux/alsa_wrapper.cc b/media/audio/linux/alsa_wrapper.cc
index 9e056d8357cda32b5827d58fa67b79b949cecdf5..67331b4b17d407dcfacb4c6942ed54f77505105f 100644
--- a/media/audio/linux/alsa_wrapper.cc
+++ b/media/audio/linux/alsa_wrapper.cc
@@ -6,6 +6,8 @@
 
 #include <alsa/asoundlib.h>
 
+namespace media {
+
 AlsaWrapper::AlsaWrapper() {
 }
 
@@ -226,3 +228,5 @@ int AlsaWrapper::MixerSelemGetCaptureVolumeRange(snd_mixer_elem_t* elem,
                                                  long* min, long* max) {
   return snd_mixer_selem_get_capture_volume_range(elem, min, max);
 }
+
+}  // namespace media