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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
      6 #define CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/callback.h"
     10 #include "chrome/common/extensions/api/audio.h"
     11 
     12 namespace extensions {
     13 
     14 typedef std::vector<linked_ptr<api::audio::OutputDeviceInfo> > OutputInfo;
     15 typedef std::vector<linked_ptr<api::audio::InputDeviceInfo> > InputInfo;
     16 typedef std::vector<std::string> DeviceIdList;
     17 
     18 class AudioService {
     19  public:
     20   class Observer {
     21    public:
     22     // Called when anything changes to the audio device configuration.
     23     virtual void OnDeviceChanged() = 0;
     24 
     25    protected:
     26     virtual ~Observer() {}
     27   };
     28 
     29   // Callback type for completing to get audio device information.
     30   typedef base::Callback<void(const OutputInfo&, const InputInfo&, bool)>
     31       GetInfoCallback;
     32 
     33   // Creates a platform-specific AudioService instance.
     34   static AudioService* CreateInstance();
     35 
     36   virtual ~AudioService() {}
     37 
     38   // Called by listeners to this service to add/remove themselves as observers.
     39   virtual void AddObserver(Observer* observer) = 0;
     40   virtual void RemoveObserver(Observer* observer) = 0;
     41 
     42   // Start to query audio device information. Should be called on UI thread.
     43   // The |callback| will be invoked once the query is completed.
     44   virtual void StartGetInfo(const GetInfoCallback& callback) = 0;
     45 
     46   // Sets the active nodes to the nodes specified by |device_list|.
     47   // It can pass in the "complete" active node list of either input
     48   // nodes, or output nodes, or both. If only input nodes are passed in,
     49   // it will only change the input nodes' active status, output nodes will NOT
     50   // be changed; similarly for the case if only output nodes are passed.
     51   // If the nodes specified in |new_active_ids| are already active, they will
     52   // remain active. Otherwise, the old active nodes will be de-activated before
     53   // we activate the new nodes with the same type(input/output).
     54   virtual void SetActiveDevices(const DeviceIdList& device_list) = 0;
     55 
     56   // Set the muted and volume/gain properties of a device.
     57   virtual bool SetDeviceProperties(const std::string& device_id,
     58                                    bool muted,
     59                                    int volume,
     60                                    int gain) = 0;
     61 
     62  protected:
     63   AudioService() {}
     64 
     65   DISALLOW_COPY_AND_ASSIGN(AudioService);
     66 };
     67 
     68 
     69 }  // namespace extensions
     70 
     71 #endif  // CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
     72