Audio extension API.

chrome/browser/extensions/api/audio/audio_service.h

Index: chrome/browser/extensions/api/audio/audio_service.h
diff --git a/chrome/browser/extensions/api/audio/audio_service.h b/chrome/browser/extensions/api/audio/audio_service.h
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+++ b/chrome/browser/extensions/api/audio/audio_service.h
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+// 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 CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
+#define CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "chrome/common/extensions/api/audio.h"
+
+namespace extensions {
+
+typedef std::vector<linked_ptr<api::audio::OutputDeviceInfo> > OutputInfo;
+typedef std::vector<linked_ptr<api::audio::InputDeviceInfo> > InputInfo;
+
+class AudioService {
+ public:
+  class Observer {
+   public:
+    // Called when anything changes to the audio device configuration.
+    virtual void OnDeviceChanged() = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  // Callback type for completing to get audio device information.
+  typedef base::Callback<void(const OutputInfo&, const InputInfo&, bool)>
+      GetInfoCallback;
+
+  // Creates a platform-specific AudioService instance.
+  static AudioService* CreateInstance();
+
+  virtual ~AudioService() {}
+
+  // Called by listeners to this service to add/remove themselves as observers.
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+
+  // Start to query audio device information. Should be called on UI thread.
+  // The |callback| will be invoked once the query is completed.
+  virtual void StartGetInfo(const GetInfoCallback& callback) = 0;
+
+ protected:
+  AudioService() {}
+
+  DISALLOW_COPY_AND_ASSIGN(AudioService);
+};
+
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_AUDIO_AUDIO_SERVICE_H_