Merge AssociateStreamWithProducer message into CreateStream message for both audio output and input.

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 330a1b476ba4184f5f0e569472c08446ebc4ede6..bb6d7a244137c4610ffdfeca2d0fe19b183de2db 100644
--- a/content/common/media/audio_messages.h
+++ b/content/common/media/audio_messages.h
@@ -91,28 +91,27 @@ IPC_MESSAGE_CONTROL2(AudioInputMsg_NotifyDeviceStarted,
 
 // Messages sent from the renderer to the browser.
 
-// Request that got sent to browser for creating an audio output stream
-IPC_MESSAGE_CONTROL2(AudioHostMsg_CreateStream,
+// Request that is sent to the browser for creating an audio output stream.
+// |render_view_id| is the routing ID for the render view producing the audio
+// data.
+IPC_MESSAGE_CONTROL3(AudioHostMsg_CreateStream,
                      int /* stream_id */,
+                     int /* render_view_id */,
                      media::AudioParameters /* params */)
 
-// Request that got sent to browser for creating an audio input stream
-IPC_MESSAGE_CONTROL4(AudioInputHostMsg_CreateStream,
+// Request that is sent to the browser for creating an audio input stream.
+// |render_view_id| is the routing ID for the render view consuming the audio
+// data.
+//
+// TODO(miu): Passing device_id to/from the render process violates abstraction
+// layers.  http://crbug.com/179597
+IPC_MESSAGE_CONTROL5(AudioInputHostMsg_CreateStream,
                      int /* stream_id */,
+                     int /* render_view_id */,
                      media::AudioParameters /* params */,
                      std::string /* device_id */,

[palmer, 2013/03/05 21:09:32]

Does this really need to be a string? What form do device IDs take? It's always
better to send a more constrained type, and not to make the other side do any
parsing.

[miu, 2013/03/06 22:36:52]

Absolutely 100% agree with you.  See the TODO comment a few lines above.  We
actually want to remove it altogether.  ;-)

[palmer, 2013/03/06 23:11:59]

Ok. I'll be your eager LGTMer for IPC security on that review. :)

                      bool /* automatic_gain_control */)
 
-// Indicate that audio for a stream is produced by the specified render view.
-IPC_MESSAGE_CONTROL2(AudioHostMsg_AssociateStreamWithProducer,
-                     int /* stream_id */,
-                     int /* render_view_id */)
-
-// Indicate that audio for a stream is consumed by the specified render view.
-IPC_MESSAGE_CONTROL2(AudioInputHostMsg_AssociateStreamWithConsumer,
-                     int /* stream_id */,
-                     int /* render_view_id */)
-
 // Start buffering and play the audio stream specified by stream_id.
 IPC_MESSAGE_CONTROL1(AudioHostMsg_PlayStream,
                      int /* stream_id */)