Notify hotwording extension of microphone state change.

This CL notifies the hotwording extension of a microphone state change
by adding a hotwordPrivate.onMicrophoneStateChanged event which triggers
an update of the hotwording state.

It also moves the media device observation from HotwordServiceFactory to
HotwordService.

BUG=461787
TBR=estade@chromium.org

Review URL: https://codereview.chromium.org/1047973003

Cr-Commit-Position: refs/heads/master@{#324024}

9 files changed, 95 insertions, 76 deletions

diff --git a/chrome/browser/extensions/api/hotword_private/hotword_private_api.cc b/chrome/browser/extensions/api/hotword_private/hotword_private_api.cc
index d38013a..7ea2b0b 100644
--- a/chrome/browser/extensions/api/hotword_private/hotword_private_api.cc
+++ b/chrome/browser/extensions/api/hotword_private/hotword_private_api.cc
@@ -106,11 +106,21 @@ void HotwordPrivateEventService::OnSpeakerModelExists() {
   SignalEvent(api::hotword_private::OnSpeakerModelExists::kEventName);
 }
 
+void HotwordPrivateEventService::OnMicrophoneStateChanged(bool enabled) {
+  SignalEvent(api::hotword_private::OnMicrophoneStateChanged::kEventName,
+              api::hotword_private::OnMicrophoneStateChanged::Create(enabled));
+}
+
 void HotwordPrivateEventService::SignalEvent(const std::string& event_name) {
+  SignalEvent(event_name, make_scoped_ptr(new base::ListValue()));
+}
+
+void HotwordPrivateEventService::SignalEvent(const std::string& event_name,
+                                             scoped_ptr<base::ListValue> args) {
   EventRouter* router = EventRouter::Get(profile_);
   if (!router || !router->HasEventListener(event_name))
     return;
-  scoped_ptr<base::ListValue> args(new base::ListValue());
+
   scoped_ptr<Event> event(new Event(event_name, args.Pass()));
   router->BroadcastEvent(event.Pass());
 }
diff --git a/chrome/browser/extensions/api/hotword_private/hotword_private_api.h b/chrome/browser/extensions/api/hotword_private/hotword_private_api.h
index 1272ded..d25b5b7 100644
--- a/chrome/browser/extensions/api/hotword_private/hotword_private_api.h
+++ b/chrome/browser/extensions/api/hotword_private/hotword_private_api.h
@@ -44,10 +44,14 @@ class HotwordPrivateEventService : public BrowserContextKeyedAPI {
 
   void OnSpeakerModelExists();
 
+  void OnMicrophoneStateChanged(bool enabled);
+
  private:
   friend class BrowserContextKeyedAPIFactory<HotwordPrivateEventService>;
 
   void SignalEvent(const std::string& event_name);
+  void SignalEvent(const std::string& event_name,
+                   scoped_ptr<base::ListValue> args);
 
   Profile* profile_;
   PrefChangeRegistrar pref_change_registrar_;
diff --git a/chrome/browser/resources/hotword/page_audio_manager.js b/chrome/browser/resources/hotword/page_audio_manager.js
index a845828..067ff4e 100644
--- a/chrome/browser/resources/hotword/page_audio_manager.js
+++ b/chrome/browser/resources/hotword/page_audio_manager.js
@@ -35,6 +35,8 @@ cr.define('hotword', function() {
     this.tabCreatedListener_ = this.handleCreatedTab_.bind(this);
     this.tabUpdatedListener_ = this.handleUpdatedTab_.bind(this);
     this.tabActivatedListener_ = this.handleActivatedTab_.bind(this);
+    this.microphoneStateChangedListener_ =
+        this.handleMicrophoneStateChanged_.bind(this);
     this.windowFocusChangedListener_ = this.handleChangedWindow_.bind(this);
     this.messageListener_ = this.handleMessageFromPage_.bind(this);
 
@@ -237,6 +239,19 @@ cr.define('hotword', function() {
       this.updateTabState_();
     },
 
+    /**
+     * Handles the microphone state changing.
+     * @param {boolean} enabled Whether the microphone is now enabled.
+     * @private
+     */
+    handleMicrophoneStateChanged_: function(enabled) {
+      if (enabled) {
+        this.updateTabState_();
+        return;
+      }
+
+      this.stopHotwording_();
+    },
 
     /**
      * Handles a change in Chrome windows.
@@ -492,6 +507,8 @@ cr.define('hotword', function() {
       chrome.tabs.onActivated.addListener(this.tabActivatedListener_);
       chrome.windows.onFocusChanged.addListener(
           this.windowFocusChangedListener_);
+      chrome.hotwordPrivate.onMicrophoneStateChanged.addListener(
+          this.microphoneStateChangedListener_);
       if (chrome.runtime.onMessage.hasListener(this.messageListener_))
         return;
       chrome.runtime.onMessageExternal.addListener(
@@ -509,6 +526,8 @@ cr.define('hotword', function() {
       chrome.tabs.onActivated.removeListener(this.tabActivatedListener_);
       chrome.windows.onFocusChanged.removeListener(
           this.windowFocusChangedListener_);
+      chrome.hotwordPrivate.onMicrophoneStateChanged.removeListener(
+          this.microphoneStateChangedListener_);
       // Don't remove the Message listener, as we want them listening all
       // the time,
     },
diff --git a/chrome/browser/search/hotword_service.cc b/chrome/browser/search/hotword_service.cc
index 6ee699f..db9d85f 100644
--- a/chrome/browser/search/hotword_service.cc
+++ b/chrome/browser/search/hotword_service.cc
@@ -323,6 +323,8 @@ void HotwordService::HotwordWebstoreInstaller::Shutdown() {
 HotwordService::HotwordService(Profile* profile)
     : profile_(profile),
       extension_registry_observer_(this),
+      microphone_available_(false),
+      audio_device_state_updated_(false),
       client_(NULL),
       error_message_(0),
       reinstall_pending_(false),
@@ -386,6 +388,13 @@ HotwordService::HotwordService(Profile* profile)
         session_observer_.get());
   }
 #endif
+
+  // Register with the device observer list to update the microphone
+  // availability.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&HotwordService::InitializeMicrophoneObserver,
+                 base::Unretained(this)));
 }
 
 HotwordService::~HotwordService() {
@@ -456,6 +465,10 @@ std::string HotwordService::ReinstalledExtensionId() {
   return extension_misc::kHotwordSharedModuleId;
 }
 
+void HotwordService::InitializeMicrophoneObserver() {
+  MediaCaptureDevicesDispatcher::GetInstance()->AddObserver(this);
+}
+
 void HotwordService::InstalledFromWebstoreCallback(
     int num_tries,
     bool success,
@@ -605,19 +618,16 @@ bool HotwordService::IsServiceAvailable() {
 
   RecordErrorMetrics(error_message_);
 
-  // Determine if the proper audio capabilities exist.
-  // The first time this is called, it probably won't return in time, but that's
-  // why it won't be included in the error calculation (i.e., the call to
-  // IsAudioDeviceStateUpdated()). However, this use case is rare and typically
-  // the devices will be initialized by the time a user goes to settings.
-  bool audio_device_state_updated =
-      HotwordServiceFactory::IsAudioDeviceStateUpdated();
+  // Determine if the proper audio capabilities exist. The first time this is
+  // called, it probably won't return in time, but that's why it won't be
+  // included in the error calculation. However, this use case is rare and
+  // typically the devices will be initialized by the time a user goes to
+  // settings.
   HotwordServiceFactory::GetInstance()->UpdateMicrophoneState();
-  if (audio_device_state_updated) {
+  if (audio_device_state_updated_) {
     bool audio_capture_allowed =
         profile_->GetPrefs()->GetBoolean(prefs::kAudioCaptureAllowed);
-    if (!audio_capture_allowed ||
-        !HotwordServiceFactory::IsMicrophoneAvailable())
+    if (!audio_capture_allowed || !microphone_available_)
       error_message_ = IDS_HOTWORD_MICROPHONE_ERROR_MESSAGE;
   }
 
@@ -772,6 +782,17 @@ void HotwordService::DisableHotwordPreferences() {
   }
 }
 
+void HotwordService::OnUpdateAudioDevices(
+    const content::MediaStreamDevices& devices) {
+  bool microphone_was_available = microphone_available_;
+  microphone_available_ = !devices.empty();
+  audio_device_state_updated_ = true;
+  HotwordPrivateEventService* event_service =
+      BrowserContextKeyedAPIFactory<HotwordPrivateEventService>::Get(profile_);
+  if (event_service && microphone_was_available != microphone_available_)
+    event_service->OnMicrophoneStateChanged(microphone_available_);
+}
+
 void HotwordService::OnHotwordAlwaysOnSearchEnabledChanged(
     const std::string& pref_name) {
   // If the pref for always on has been changed in some way, that means that
diff --git a/chrome/browser/search/hotword_service.h b/chrome/browser/search/hotword_service.h
index 9b22c84..2d2394a 100644
--- a/chrome/browser/search/hotword_service.h
+++ b/chrome/browser/search/hotword_service.h
@@ -12,6 +12,7 @@
 #include "base/prefs/pref_change_registrar.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/extensions/webstore_startup_installer.h"
+#include "chrome/browser/media/media_capture_devices_dispatcher.h"
 #include "chrome/common/extensions/webstore_install_result.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
@@ -38,7 +39,8 @@ extern const char kHotwordTrainingEnabled[];
 
 // Provides an interface for the Hotword component that does voice triggered
 // search.
-class HotwordService : public extensions::ExtensionRegistryObserver,
+class HotwordService : public MediaCaptureDevicesDispatcher::Observer,
+                       public extensions::ExtensionRegistryObserver,
                        public KeyedService {
  public:
   // A simple subclass to allow for aborting an install during shutdown.
@@ -125,6 +127,8 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
   // no error.
   int error_message() { return error_message_; }
 
+  bool microphone_available() { return microphone_available_; }
+
   // These methods are for launching, and getting and setting the launch mode of
   // the Hotword Audio Verification App.
   //
@@ -174,6 +178,10 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
   // Turn off the currently enabled version of hotwording if one exists.
   void DisableHotwordPreferences();
 
+  // Overridden from MediaCaptureDevicesDispatcher::Observer
+  void OnUpdateAudioDevices(
+      const content::MediaStreamDevices& devices) override;
+
  protected:
   // Used in test subclasses.
   scoped_refptr<HotwordWebstoreInstaller> installer_;
@@ -181,6 +189,10 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
  private:
   class HotwordUserSessionStateObserver;
 
+  // Must be called from the UI thread since the instance of
+  // MediaCaptureDevicesDispatcher can only be accessed on the UI thread.
+  void InitializeMicrophoneObserver();
+
   // Callback for webstore extension installer.
   void InstalledFromWebstoreCallback(
       int num_tries,
@@ -207,6 +219,13 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
 
   scoped_ptr<HotwordAudioHistoryHandler> audio_history_handler_;
 
+  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_;
+
   HotwordClient* client_;
   int error_message_;
   bool reinstall_pending_;
diff --git a/chrome/browser/search/hotword_service_factory.cc b/chrome/browser/search/hotword_service_factory.cc
index 4baf2be..1aa72ac 100644
--- a/chrome/browser/search/hotword_service_factory.cc
+++ b/chrome/browser/search/hotword_service_factory.cc
@@ -59,45 +59,16 @@ int HotwordServiceFactory::GetCurrentError(BrowserContext* context) {
   return hotword_service->error_message();
 }
 
-// static
-bool HotwordServiceFactory::IsMicrophoneAvailable() {
-  return GetInstance()->microphone_available();
-}
-
-// static
-bool HotwordServiceFactory::IsAudioDeviceStateUpdated() {
-  return GetInstance()->audio_device_state_updated();
-}
-
 HotwordServiceFactory::HotwordServiceFactory()
     : BrowserContextKeyedServiceFactory(
         "HotwordService",
-        BrowserContextDependencyManager::GetInstance()),
-      microphone_available_(false),
-      audio_device_state_updated_(false) {
+        BrowserContextDependencyManager::GetInstance()) {
   // No dependencies.
-
-  // Register with the device observer list to update the microphone
-  // availability.
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&HotwordServiceFactory::InitializeMicrophoneObserver,
-                 base::Unretained(this)));
 }
 
 HotwordServiceFactory::~HotwordServiceFactory() {
 }
 
-void HotwordServiceFactory::InitializeMicrophoneObserver() {
-  MediaCaptureDevicesDispatcher::GetInstance()->AddObserver(this);
-}
-
-void HotwordServiceFactory::OnUpdateAudioDevices(
-    const content::MediaStreamDevices& devices) {
-  microphone_available_ = !devices.empty();
-  audio_device_state_updated_ = true;
-}
-
 void HotwordServiceFactory::UpdateMicrophoneState() {
   // In order to trigger the monitor, just call getAudioCaptureDevices.
   content::MediaStreamDevices devices =
diff --git a/chrome/browser/search/hotword_service_factory.h b/chrome/browser/search/hotword_service_factory.h
index 08d325f..3489296 100644
--- a/chrome/browser/search/hotword_service_factory.h
+++ b/chrome/browser/search/hotword_service_factory.h
@@ -6,15 +6,13 @@
 #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);
@@ -34,19 +32,6 @@ class HotwordServiceFactory : public MediaCaptureDevicesDispatcher::Observer,
   // 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
@@ -67,21 +52,6 @@ class HotwordServiceFactory : public MediaCaptureDevicesDispatcher::Observer,
   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);
 };
 
diff --git a/chrome/browser/ui/webui/voice_search_ui.cc b/chrome/browser/ui/webui/voice_search_ui.cc
index 6731445..b676d3b 100644
--- a/chrome/browser/ui/webui/voice_search_ui.cc
+++ b/chrome/browser/ui/webui/voice_search_ui.cc
@@ -270,9 +270,11 @@ class VoiceSearchDomHandler : public WebUIMessageHandler {
 
     AddPair(list, "NaCl Enabled", nacl_enabled);
 
-    AddPair(list,
-            "Microphone",
-            HotwordServiceFactory::IsMicrophoneAvailable() ? "Yes" : "No");
+    HotwordService* hotword_service =
+        HotwordServiceFactory::GetForProfile(profile_);
+    AddPair(list, "Microphone",
+            hotword_service && hotword_service->microphone_available() ? "Yes"
+                                                                       : "No");
 
     std::string audio_capture = "No";
     if (profile_->GetPrefs()->GetBoolean(prefs::kAudioCaptureAllowed))
diff --git a/chrome/common/extensions/api/hotword_private.idl b/chrome/common/extensions/api/hotword_private.idl
index 012ad64..a7ffeb1 100644
--- a/chrome/common/extensions/api/hotword_private.idl
+++ b/chrome/common/extensions/api/hotword_private.idl
@@ -182,5 +182,8 @@ namespace hotwordPrivate {
     // Fired when the browser wants to find out whether the speaker model
     // exists.
     static void onSpeakerModelExists();
+
+    // Fired when the microphone state changes.
+    static void onMicrophoneStateChanged(boolean enabled);
   };
 };