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

content/renderer/media/audio_message_filter.h

Index: content/renderer/media/audio_message_filter.h
diff --git a/content/renderer/media/audio_message_filter.h b/content/renderer/media/audio_message_filter.h
index 2d9f4a2662eeb94e7740c7c1eeb18bc4d0c7bf3d..08aab4ec0fa82d381337a11bc64c356780678303 100644
--- a/content/renderer/media/audio_message_filter.h
+++ b/content/renderer/media/audio_message_filter.h
@@ -6,8 +6,7 @@
 #define CONTENT_RENDERER_MEDIA_AUDIO_MESSAGE_FILTER_H_
 
 #include "base/gtest_prod_util.h"
-#include "base/hash_tables.h"
-#include "base/message_loop_proxy.h"
+#include "base/id_map.h"
 #include "base/shared_memory.h"
 #include "base/sync_socket.h"
 #include "base/synchronization/lock.h"
@@ -27,8 +26,7 @@ namespace content {
 // IO thread (secondary thread of render process) it intercepts audio messages
 // and process them on IO thread since these messages are time critical.
 class CONTENT_EXPORT AudioMessageFilter
-    : public IPC::ChannelProxy::MessageFilter,
-      public NON_EXPORTED_BASE(media::AudioOutputIPC) {
+    : public IPC::ChannelProxy::MessageFilter {
  public:
   explicit AudioMessageFilter(
       const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
@@ -36,27 +34,12 @@ class CONTENT_EXPORT AudioMessageFilter
   // Getter for the one AudioMessageFilter object.
   static AudioMessageFilter* Get();
 
-  // Associates |render_view_id| as the source of audio rendered for a stream.
-  void AssociateStreamWithProducer(int stream_id, int render_view_id);
-
-  // media::AudioOutputIPC implementation.
-  virtual int AddDelegate(media::AudioOutputIPCDelegate* delegate) OVERRIDE;
-  virtual void RemoveDelegate(int id) OVERRIDE;
-
-  // Methods below must be called on the provided |io_message_loop|.
-  virtual void CreateStream(int stream_id,
-                            const media::AudioParameters& params) OVERRIDE;
-  virtual void PlayStream(int stream_id) OVERRIDE;
-  virtual void PauseStream(int stream_id) OVERRIDE;
-  virtual void FlushStream(int stream_id) OVERRIDE;
-  virtual void CloseStream(int stream_id) OVERRIDE;
-  virtual void SetVolume(int stream_id, double volume) OVERRIDE;
-
-  // IPC::ChannelProxy::MessageFilter override. Called on |io_message_loop|.
-  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
-  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
-  virtual void OnFilterRemoved() OVERRIDE;
-  virtual void OnChannelClosing() OVERRIDE;
+  // Create an AudioOutputIPC for a delegate.  |render_view_id| is the render
+  // view containing the entity producing the audio.
+  //
+  // The returned object is not thread-safe.  Methods must be called on
+  // |io_message_loop|.
+  media::AudioOutputIPC* CreateAudioOutputIPC(int render_view_id);
 
   // When set, AudioMessageFilter will update the AudioHardwareConfig with new
   // configuration values as recieved by OnOutputDeviceChanged().  The provided
@@ -75,9 +58,19 @@ class CONTENT_EXPORT AudioMessageFilter
   FRIEND_TEST_ALL_PREFIXES(AudioMessageFilterTest, Basic);
   FRIEND_TEST_ALL_PREFIXES(AudioMessageFilterTest, Delegates);
 
+  // Implementation of media::AudioOutputIPC which augments IPC calls with
+  // stream_id and the source render_view_id.
+  class AudioOutputIPCImpl;

[DaleCurtis, 2013/03/01 00:27:52]

What's the point of nesting this? Seems it should just be entirely inside the
message filter.

[miu, 2013/03/02 00:24:16]

I needed it to have access to private members (the Send() method, and delegates_
IDMap).  I could also just "friend" the class.  I feel that making it a nested
class better communicates the structure of the program, but it wouldn't kill me
to change it if you strongly prefer some other way.

+
   // Sends an IPC message using |channel_|.
   void Send(IPC::Message* message);
 
+  // IPC::ChannelProxy::MessageFilter override. Called on |io_message_loop|.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
+  virtual void OnFilterRemoved() OVERRIDE;
+  virtual void OnChannelClosing() OVERRIDE;
+
   // Received when browser process has created an audio output stream.
   void OnStreamCreated(int stream_id, base::SharedMemoryHandle handle,
 #if defined(OS_WIN)
@@ -99,20 +92,16 @@ class CONTENT_EXPORT AudioMessageFilter
   // The singleton instance for this filter.
   static AudioMessageFilter* filter_;
 
-  // IPC channel for Send(), must only be accesed on |io_message_loop_|.
+  // IPC channel for Send(); must only be accesed on |io_message_loop_|.
   IPC::Channel* channel_;
 
-  // Unique ID to use for next added delegate.
-  int next_stream_id_;
-
-  // Guards all variables below which are accessed from multiple threads.
-  base::Lock lock_;
-
-  // A map of stream ids to delegates.
-  typedef base::hash_map<int, media::AudioOutputIPCDelegate*> DelegateMap;
-  DelegateMap delegates_;
+  // A map of stream ids to delegates; must only be accessed on
+  // |io_message_loop_|.
+  IDMap<media::AudioOutputIPCDelegate> delegates_;
 
   // Audio hardware configuration to update when OnOutputDeviceChanged() fires.
+  // Access is guarded by |lock_|.
+  base::Lock lock_;
   media::AudioHardwareConfig* audio_hardware_config_;
 
   // Message loop on which IPC calls are driven.