First step towards moving AudioDevice from content/ to media/audio.

content/common/media/audio_messages.h

Index: content/common/media/audio_messages.h
diff --git a/content/common/media/audio_messages.h b/content/common/media/audio_messages.h
index ce0d4bd68f1c475d6f4113cc6d78d0190835b1d6..36de1bf4b93f67441f3cc060e7590807edd97a78 100644
--- a/content/common/media/audio_messages.h
+++ b/content/common/media/audio_messages.h
@@ -12,16 +12,16 @@
 #include "base/sync_socket.h"
 #include "content/common/content_export.h"
 #include "content/common/media/audio_param_traits.h"
-#include "content/common/media/audio_stream_state.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/audio/audio_buffers_state.h"
+#include "media/audio/audio_device_ipc.h"
 #include "media/audio/audio_parameters.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START AudioMsgStart
 
-IPC_ENUM_TRAITS(AudioStreamState)
+IPC_ENUM_TRAITS(media::AudioStreamState)
 
 IPC_STRUCT_TRAITS_BEGIN(media::AudioBuffersState)
   IPC_STRUCT_TRAITS_MEMBER(pending_bytes)
@@ -70,12 +70,12 @@ IPC_MESSAGE_CONTROL4(AudioInputMsg_NotifyStreamCreated,
 // update after the renderer has requested a Create/Start/Close.
 IPC_MESSAGE_CONTROL2(AudioMsg_NotifyStreamStateChanged,
                      int /* stream id */,
-                     AudioStreamState /* new state */)
+                     media::AudioStreamState /* new state */)
 
 // Notification message sent from browser to renderer for state update.
 IPC_MESSAGE_CONTROL2(AudioInputMsg_NotifyStreamStateChanged,
                      int /* stream id */,
-                     AudioStreamState /* new state */)
+                     media::AudioStreamState /* new state */)
 
 IPC_MESSAGE_CONTROL2(AudioInputMsg_NotifyStreamVolume,
                      int /* stream id */,