Link things together and enable the device selection for linux and mac.

content/renderer/media/audio_input_device.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Low-latency audio capturing unit utilizing audio input stream provided
 // by browser process through IPC.
 //
 // Relationship of classes:
 //
 //  AudioInputController                 AudioInputDevice
@@ skipping 82 matching lines @@
    public:
     virtual void Capture(const std::vector<float*>& audio_data,
                          size_t number_of_frames,
                          size_t audio_delay_milliseconds) = 0;
    protected:
     virtual ~CaptureCallback() {}
   };
 
   class CONTENT_EXPORT CaptureEventHandler {
    public:
-    // Notification to the client that the device with the specific index has
-    // been started. This callback is triggered as a result of StartDevice().
-    virtual void OnDeviceStarted(int device_index) = 0;
+    // Notification to the client that the device with the specific |device_id|
+    // has been started.
+    // This callback is triggered as a result of StartDevice().
+    virtual void OnDeviceStarted(const std::string& device_id) = 0;
 
     // Notification to the client that the device has been stopped.
     virtual void OnDeviceStopped() = 0;
 
    protected:
     virtual ~CaptureEventHandler() {}
   };
 
   // Methods called on main render thread -------------------------------------
   AudioInputDevice(size_t buffer_size,
@@ skipping 28 matching lines @@
   double sample_rate() const { return audio_parameters_.sample_rate; }
   size_t buffer_size() const { return audio_parameters_.samples_per_packet; }
 
   // Methods called on IO thread ----------------------------------------------
   // AudioInputMessageFilter::Delegate impl., called by AudioInputMessageFilter
   virtual void OnLowLatencyCreated(base::SharedMemoryHandle handle,
                                    base::SyncSocket::Handle socket_handle,
                                    uint32 length);
   virtual void OnVolume(double volume);
   virtual void OnStateChanged(AudioStreamState state);
-  virtual void OnDeviceReady(int index);
+  virtual void OnDeviceReady(const std::string& device_id);
 
  private:
   // Methods called on IO thread ----------------------------------------------
   // The following methods are tasks posted on the IO thread that needs to
   // be executed on that thread. They interact with AudioInputMessageFilter and
   // sends IPC messages on that thread.
   void InitializeOnIOThread();
   void SetSessionIdOnIOThread(int session_id);
   void StartOnIOThread();
   void ShutDownOnIOThread(base::WaitableEvent* completion);
@@ skipping 47 matching lines @@
   // callback. Only modified on the IO thread.
   bool pending_device_ready_;
 
   scoped_ptr<base::SharedMemory> shared_memory_;
   scoped_ptr<base::SyncSocket> socket_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_INPUT_DEVICE_H_