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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   // Set the devices in the following list as active. This will only pick
     47   // the first input and first active devices to set to active.
     48   virtual void SetActiveDevices(const DeviceIdList& device_list) = 0;
     49 
     50   // Set the muted and volume/gain properties of a device.
     51   virtual bool SetDeviceProperties(const std::string& device_id,
     52                                    bool muted,
     53                                    int volume,
     54                                    int gain) = 0;
     55 
     56  protected:
     57   AudioService() {}
     58 
     59   DISALLOW_COPY_AND_ASSIGN(AudioService);
     60 };
     61 
     62 
     63 }  // namespace extensions
     64 
     65 #endif  // CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
     66