Notify hotwording extension of microphone state change.

chrome/browser/search/hotword_service_factory.h

 // Copyright 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_SEARCH_HOTWORD_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
-#include "chrome/browser/media/media_capture_devices_dispatcher.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
 class HotwordService;
 class Profile;
 
 // Singleton that owns all HotwordServices and associates them with Profiles.
-class HotwordServiceFactory : public MediaCaptureDevicesDispatcher::Observer,
-                              public BrowserContextKeyedServiceFactory {
+class HotwordServiceFactory : public BrowserContextKeyedServiceFactory {
  public:
   // Returns the HotwordService for |context|.
   static HotwordService* GetForProfile(content::BrowserContext* context);
 
   static HotwordServiceFactory* GetInstance();
 
   // Returns true if the hotwording service is available for |context|.
   static bool IsServiceAvailable(content::BrowserContext* context);
 
   // Returns true if hotwording is allowed for |context|.
   static bool IsHotwordAllowed(content::BrowserContext* context);
 
   // Returns whether always-on hotwording is available.
   static bool IsAlwaysOnAvailable();
 
   // Returns the current error message for the service for |context|.
   // A value of 0 indicates no error.
   static int GetCurrentError(content::BrowserContext* context);
 
-  // Returns the current known state of the microphone. Since this state
-  // is browser (not profile) specific, it resides in the factory.
-  static bool IsMicrophoneAvailable();
-
-  // Returns whether the state of the audio devices has been updated.
-  // Essentially it indicates the validity of the return value from
-  // IsMicrophoneAvailable().
-  static bool IsAudioDeviceStateUpdated();
-
-  // Overridden from MediaCaptureDevicesDispatcher::Observer
-  void OnUpdateAudioDevices(
-      const content::MediaStreamDevices& devices) override;
-
   // This will kick off the monitor that calls OnUpdateAudioDevices when the
   // number of audio devices changes (or is initialized). It needs to be a
   // separate function so it can be called after the service is initialized
   // (i.e., after startup). The monitor can't be initialized during startup
   // because it would slow down startup too much so it is delayed and not
   // called until it's needed by the webui in browser_options_handler.
   void UpdateMicrophoneState();
 
  private:
   friend struct DefaultSingletonTraits<HotwordServiceFactory>;
 
   HotwordServiceFactory();
   ~HotwordServiceFactory() override;
 
   // Overrides from BrowserContextKeyedServiceFactory:
   void RegisterProfilePrefs(
       user_prefs::PrefRegistrySyncable* registry) override;
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
 
-  // Must be called from the UI thread since the instance of
-  // MediaCaptureDevicesDispatcher can only be accessed on the UI thread.
-  void InitializeMicrophoneObserver();
-
-  bool microphone_available() { return microphone_available_; }
-
-  bool microphone_available_;
-
-  // Indicates if the check for audio devices has been run such that it can be
-  // included in the error checking. Audio checking is not done immediately
-  // upon start up because of the negative impact on performance.
-  bool audio_device_state_updated_;
-
-  bool audio_device_state_updated() { return audio_device_state_updated_; }
-
   DISALLOW_COPY_AND_ASSIGN(HotwordServiceFactory);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_FACTORY_H_