Add ability to active multiple devices via the audio API.

chromeos/dbus/cras_audio_client.h

 // Copyright (c) 2013 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.
 
 #ifndef CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_
 #define CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_
 
 #include "base/callback.h"
 #include "base/observer_list.h"
 #include "chromeos/chromeos_export.h"
@@ skipping 87 matching lines @@
   // Adds input node |node_id| to the active input list. This is used to add
   // an additional active input node besides the one set by SetActiveInputNode.
   // Note that this action will not trigger an ActiveInputNodeChanged event and
   // nothing will happen if the |node_id| has already been set as active.
   virtual void AddActiveInputNode(uint64 node_id) = 0;
 
   // Removes input node |node_id| from the active input list. This is used for
   // removing an active input node added by AddActiveInputNode.
   virtual void RemoveActiveInputNode(uint64 node_id) = 0;
 
+  // Adds input node |node_id| to the active outputs list. This is used to add
+  // an additional active output node besides the one set by SetActiveInputNode.
+  // Note that this action will not trigger an ActiveOutputNodeChanged event
+  // and nothing will happen if the |node_id| has already been set as active.
+  virtual void AddActiveOutputNode(uint64 node_id) = 0;
+
+  // Removes output node |node_id| from the active output list. This is used for
+  // removing an active output node added by AddActiveOutputNode.
+  virtual void RemoveActiveOutputNode(uint64 node_id) = 0;
+
   // Creates the instance.
   static CrasAudioClient* Create();
 
  protected:
   // Create() should be used instead.
   CrasAudioClient();
 
  private:
 
   DISALLOW_COPY_AND_ASSIGN(CrasAudioClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_