Update microphone sw switch notification text

This CL updates the text in the microphone mute notification for the
software switch. Please visit go/privacy-hub-strings for detailed specs.

Bug: b/257202314
Change-Id: Ib2d7ce70b0a755686e0be574522225bc53838980
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4028660
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Md Shahadat Hossain Shahin <shahinmd@google.com>
Cr-Commit-Position: refs/heads/main@{#1075250}

ash/ash_strings.grd

@@ -4515,13 +4515,16 @@ Here are some things you can try to get started.
 
       <!-- Strings for microphone mute switch notification -->
       <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_TITLE" desc="Title for a notification shown to the users when an app tries to use the microphone while the microphone is muted.i Similar to IDS_MICROPHONE_MUTED_NOTIFICATION_TITLE_WITH_APP_NAME, except this message contains a generic app name string. Used when the name of the app that's using the microphone cannot be determined.">
-          Turn on microphone access?
+        Turn on microphone access?
       </message>
       <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE" desc="Message for a notification shown to the users when an app tries to use the microphone while the microphone is muted.">
-        Allows microphone access for all apps and websites with the microphone permission
+        This allows microphone access for all apps and websites with the microphone permission
       </message>
-      <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_APP_NAME" desc="Message for a notification shown to the users when an app tries to use the microphone while the microphone is muted.">
-        Allows microphone access for <ph name="APP_NAME">$1<ex>Zoom</ex></ph> and all apps and websites with the microphone permission
+      <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_ONE_APP_NAME" desc="Message for the notification shown to the users when an app tries to use the microphone while the microphone is muted.">
+        This allows microphone access for <ph name="APP_NAME">$1<ex>Zoom</ex></ph> and all apps and websites with the microphone permission
+      </message>
+      <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_TWO_APP_NAMES" desc="Message for the notification shown to the users when multiple apps try to use the microphone while the microphone is muted.">
+        This allows microphone access for <ph name="APP1_NAME">$1<ex>Zoom</ex></ph>, <ph name="APP2_NAME">$2<ex>Snapchat</ex></ph>, and all apps and websites with the microphone permission
       </message>
       <message name="IDS_MICROPHONE_MUTED_NOTIFICATION_ACTION_BUTTON" desc="Label for an action button in a notification shown to the users when an app tries to use the microphone while the microphone is muted. The button, when tapped unmutes the microphone.">
         Turn on microphone access

ash/ash_strings_grd/IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE.png.sha1

@@ -1 +1 @@
-37d686b7a7166fe7d6563b34d37e93343f870236
+09afee5f32b001236ade8298d171dff0575792f0

ash/ash_strings_grd/IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_APP_NAME.png.sha1

@@ -1 +0,0 @@
-a3f5dd22925b6f620dd7d349dcc8fea011dd9faa

ash/ash_strings_grd/IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_ONE_APP_NAME.png.sha1

@@ -0,0 +1 @@
+abdd18b19fa5906ba9bef3fb9491e830ea160dc5

ash/ash_strings_grd/IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_TWO_APP_NAMES.png.sha1

@@ -0,0 +1 @@
+bb9cbefc0cbd8068e9f507e5c21a975810bcddef

ash/public/cpp/microphone_mute_notification_delegate.h

@@ -6,6 +6,7 @@
 #define ASH_PUBLIC_CPP_MICROPHONE_MUTE_NOTIFICATION_DELEGATE_H_
 
 #include <string>
+#include <vector>
 
 #include "ash/public/cpp/ash_public_export.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
@@ -19,13 +20,11 @@ class ASH_PUBLIC_EXPORT MicrophoneMuteNotificationDelegate {
  public:
   static MicrophoneMuteNotificationDelegate* Get();
 
-  // Returns an optional string with:
-  //
-  // No value, if no app is accessing the mic
-  // Empty value, if an app is accessing the mic but no name could be determined
-  // Non-empty value, if an app is accessing the mic and a name could be
-  // determined
-  virtual absl::optional<std::u16string> GetAppAccessingMicrophone() = 0;
+  // Returns a list of names of the applications that have attempted to use the
+  // microphone, in order of most-recently-launched. If an application is
+  // accessing the microphone but no name could be determined, the name of that
+  // application will not be in the returned list.
+  virtual std::vector<std::u16string> GetAppsAccessingMicrophone() = 0;
 
  protected:
   MicrophoneMuteNotificationDelegate();

ash/system/microphone_mute/microphone_mute_notification_controller.cc

@@ -6,6 +6,7 @@
 
 #include <cstdint>
 #include <string>
+#include <vector>
 
 #include "ash/constants/notifier_catalogs.h"
 #include "ash/public/cpp/microphone_mute_notification_delegate.h"
@@ -92,14 +93,14 @@ void MicrophoneMuteNotificationController::MaybeShowNotification(
     // `MicrophoneMuteNotificationDelegate` is not created in guest mode.
     if (!microphone_mute_notification_delegate)
       return;
-    absl::optional<std::u16string> app_name =
-        microphone_mute_notification_delegate->GetAppAccessingMicrophone();
-    if (app_name.has_value() || input_stream_count_) {
+    std::vector<std::u16string> app_names =
+        microphone_mute_notification_delegate->GetAppsAccessingMicrophone();
+    if (!app_names.empty() || input_stream_count_) {
       if (recreate)
         RemoveMicrophoneMuteNotification();
 
       std::unique_ptr<message_center::Notification> notification =
-          GenerateMicrophoneMuteNotification(app_name, priority);
+          GenerateMicrophoneMuteNotification(app_names, priority);
       message_center::MessageCenter::Get()->AddNotification(
           std::move(notification));
       return;
@@ -119,7 +120,7 @@ void MicrophoneMuteNotificationController::SetAndLogMicrophoneMute(
 
 std::unique_ptr<message_center::Notification>
 MicrophoneMuteNotificationController::GenerateMicrophoneMuteNotification(
-    const absl::optional<std::u16string>& app_name,
+    const std::vector<std::u16string>& app_names,
     message_center::NotificationPriority priority) {
   message_center::RichNotificationData notification_data;
   notification_data.priority = priority;
@@ -148,7 +149,7 @@ MicrophoneMuteNotificationController::GenerateMicrophoneMuteNotification(
   std::unique_ptr<message_center::Notification> notification =
       CreateSystemNotification(
           message_center::NOTIFICATION_TYPE_SIMPLE, kNotificationId,
-          GetNotificationTitle(), GetNotificationMessage(app_name),
+          GetNotificationTitle(), GetNotificationMessage(app_names),
           /*display_source=*/std::u16string(), GURL(),
           message_center::NotifierId(
               message_center::NotifierType::SYSTEM_COMPONENT, kNotificationId,
@@ -159,17 +160,26 @@ MicrophoneMuteNotificationController::GenerateMicrophoneMuteNotification(
 }
 
 std::u16string MicrophoneMuteNotificationController::GetNotificationMessage(
-    const absl::optional<std::u16string>& app_name) const {
+    const std::vector<std::u16string>& app_names) const {
   if (mic_muted_by_mute_switch_) {
     return l10n_util::GetStringUTF16(
         IDS_MICROPHONE_MUTE_SWITCH_ON_NOTIFICATION_MESSAGE);
   }
-  if (app_name.value_or(u"").empty()) {
-    return l10n_util::GetStringUTF16(IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE);
+
+  if (app_names.size() == 1) {
+    return l10n_util::GetStringFUTF16(
+        IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_ONE_APP_NAME,
+        app_names[0]);
+  } else if (app_names.size() == 2) {
+    return l10n_util::GetStringFUTF16(
+        IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_TWO_APP_NAMES,
+        app_names[0], app_names[1]);
   }
-  return l10n_util::GetStringFUTF16(
-      IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_APP_NAME,
-      app_name.value());
+
+  // If no application name can be determined or more than 2 applications are
+  // attempting to use the microphone, we display this message in the
+  // notification.
+  return l10n_util::GetStringUTF16(IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE);
 }
 
 std::u16string MicrophoneMuteNotificationController::GetNotificationTitle()

ash/system/microphone_mute/microphone_mute_notification_controller.h

@@ -58,18 +58,20 @@ class ASH_EXPORT MicrophoneMuteNotificationController
   // mic while the mic is muted.
   std::unique_ptr<message_center::Notification>
   GenerateMicrophoneMuteNotification(
-      const absl::optional<std::u16string>& app_name,
+      const std::vector<std::u16string>& app_names,
       message_center::NotificationPriority priority);
 
   // Mic mute notification title.
   std::u16string GetNotificationTitle() const;
 
   // Mic mute notification body.
-  // If the name of the app is provided via \p app_name, it may be used in the
-  // notification body. If the name is empty, a generic text that avoids
-  // refering to the app by name will be used.
+  // If the list of names of the applications attempting to use the microphone
+  // provided via \p app_names is empty or has more that two elements, a generic
+  // text without referrring to any application name will be displayed.
+  // Otherwise, the displayed text will contain 1-2 application names depending
+  // on the availability.
   std::u16string GetNotificationMessage(
-      const absl::optional<std::u16string>& app_name) const;
+      const std::vector<std::u16string>& app_names) const;
 
   // Takes down the mic mute notification.
   void RemoveMicrophoneMuteNotification();

ash/system/microphone_mute/microphone_mute_notification_controller_unittest.cc

@@ -4,10 +4,12 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "ash/constants/ash_features.h"
 #include "ash/public/cpp/microphone_mute_notification_delegate.h"
 #include "ash/public/cpp/test/test_system_tray_client.h"
+#include "ash/strings/grit/ash_strings.h"
 #include "ash/system/microphone_mute/microphone_mute_notification_controller.h"
 #include "ash/system/privacy_hub/privacy_hub_metrics.h"
 #include "ash/test/ash_test_base.h"
@@ -17,6 +19,7 @@
 #include "base/test/scoped_feature_list.h"
 #include "chromeos/ash/components/dbus/audio/fake_cras_audio_client.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/public/cpp/notification.h"
 #include "ui/message_center/public/cpp/notification_types.h"
@@ -26,16 +29,17 @@ namespace ash {
 class FakeMicrophoneMuteNotificationDelegate
     : public MicrophoneMuteNotificationDelegate {
  public:
-  absl::optional<std::u16string> GetAppAccessingMicrophone() override {
-    return app_name_;
+  std::vector<std::u16string> GetAppsAccessingMicrophone() override {
+    return app_names_;
   }
 
-  void SetAppAccessingMicrophone(
+  void AddAppAccessingMicrophone(
       const absl::optional<std::u16string> app_name) {
-    app_name_ = app_name;
+    if (app_name.has_value())
+      app_names_.insert(app_names_.begin(), app_name.value());
   }
 
-  absl::optional<std::u16string> app_name_;
+  std::vector<std::u16string> app_names_;
 };
 
 class MicrophoneMuteNotificationControllerTest : public AshTestBase {
@@ -120,7 +124,7 @@ class MicrophoneMuteNotificationControllerTest : public AshTestBase {
   }
 
   void LaunchApp(absl::optional<std::u16string> app_name) {
-    delegate_->SetAppAccessingMicrophone(app_name);
+    delegate_->AddAppAccessingMicrophone(app_name);
   }
 
   const base::HistogramTester& histogram_tester() const {
@@ -427,6 +431,68 @@ TEST_F(MicrophoneMuteNotificationControllerTest,
   EXPECT_TRUE(GetPopupNotification());
 }
 
+TEST_F(MicrophoneMuteNotificationControllerTest, NotificationContents) {
+  // No notification initially.
+  EXPECT_FALSE(GetNotification());
+
+  // Mute the mic, still no notification.
+  MuteMicrophone();
+  EXPECT_FALSE(GetNotification());
+
+  // Launch an app that's not using the mic, should be no notification.
+  LaunchApp(absl::nullopt);
+  EXPECT_FALSE(GetNotification());
+
+  // Launch an app that's using the mic, but the name of the app can not be
+  // determined.
+  LaunchApp(absl::nullopt);
+  SetNumberOfActiveInputStreams(1);
+  EXPECT_TRUE(GetNotification());
+  EXPECT_TRUE(GetPopupNotification());
+  EXPECT_EQ(l10n_util::GetStringUTF16(IDS_MICROPHONE_MUTED_NOTIFICATION_TITLE),
+            GetNotification()->title());
+  // The notification body should not contain any app name.
+  EXPECT_EQ(
+      l10n_util::GetStringUTF16(IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE),
+      GetNotification()->message());
+
+  // Launch an app that's using the mic, the name of the app can be determined.
+  LaunchApp(u"app1");
+  SetNumberOfActiveInputStreams(2);
+  EXPECT_TRUE(GetNotification());
+  EXPECT_TRUE(GetPopupNotification());
+  // The notification body should contain name of the app.
+  EXPECT_EQ(
+      l10n_util::GetStringFUTF16(
+          IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_ONE_APP_NAME, u"app1"),
+      GetNotification()->message());
+
+  // Launch another app that's using the mic, the name of the app can be
+  // determined.
+  LaunchApp(u"app2");
+  SetNumberOfActiveInputStreams(3);
+  EXPECT_TRUE(GetNotification());
+  EXPECT_TRUE(GetPopupNotification());
+  // The notification body should contain the two available app names in the
+  // order of most recently launched.
+  EXPECT_EQ(l10n_util::GetStringFUTF16(
+                IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE_WITH_TWO_APP_NAMES,
+                u"app2", u"app1"),
+            GetNotification()->message());
+
+  // Launch yet another app that's using the mic, the name of the app can be
+  // determined.
+  LaunchApp(u"app3");
+  SetNumberOfActiveInputStreams(4);
+  EXPECT_TRUE(GetNotification());
+  EXPECT_TRUE(GetPopupNotification());
+  // As more that two apps are attempting to use the microphone, we fall back to
+  // displaying the generic message in the notification.
+  EXPECT_EQ(
+      l10n_util::GetStringUTF16(IDS_MICROPHONE_MUTED_NOTIFICATION_MESSAGE),
+      GetNotification()->message());
+}
+
 TEST_F(MicrophoneMuteNotificationControllerTest, MetricCollection) {
   EXPECT_EQ(histogram_tester().GetBucketCount(
                 privacy_hub_metrics::

ash/system/privacy_hub/microphone_privacy_switch_controller_unittest.cc

@@ -4,6 +4,9 @@
 
 #include "ash/system/privacy_hub/microphone_privacy_switch_controller.h"
 
+#include <string>
+#include <vector>
+
 #include "ash/constants/ash_pref_names.h"
 #include "ash/public/cpp/microphone_mute_notification_delegate.h"
 #include "ash/public/cpp/privacy_hub_delegate.h"
@@ -26,8 +29,8 @@ namespace {
 class FakeMicrophoneMuteNotificationDelegate
     : public MicrophoneMuteNotificationDelegate {
  public:
-  absl::optional<std::u16string> GetAppAccessingMicrophone() override {
-    return absl::nullopt;
+  std::vector<std::u16string> GetAppsAccessingMicrophone() override {
+    return {};
   }
 };
 

ash/system/privacy_hub/privacy_hub_notification_controller_unittest.cc

@@ -4,6 +4,9 @@
 
 #include "ash/system/privacy_hub/privacy_hub_notification_controller.h"
 
+#include <string>
+#include <vector>
+
 #include "ash/constants/ash_features.h"
 #include "ash/public/cpp/microphone_mute_notification_delegate.h"
 #include "ash/public/cpp/test/test_system_tray_client.h"
@@ -28,8 +31,8 @@ namespace {
 class FakeMicrophoneMuteNotificationDelegate
     : public MicrophoneMuteNotificationDelegate {
  public:
-  absl::optional<std::u16string> GetAppAccessingMicrophone() override {
-    return absl::nullopt;
+  std::vector<std::u16string> GetAppsAccessingMicrophone() override {
+    return {};
   }
 };
 

chrome/browser/ui/ash/app_access_notifier.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/ui/ash/app_access_notifier.h"
 
 #include <string>
+#include <vector>
 
 #include "ash/constants/ash_features.h"
 #include "ash/system/privacy/privacy_indicators_controller.h"
@@ -78,20 +79,26 @@ AppAccessNotifier::AppAccessNotifier() {
 
 AppAccessNotifier::~AppAccessNotifier() = default;
 
-absl::optional<std::u16string> AppAccessNotifier::GetAppAccessingMicrophone() {
+std::vector<std::u16string> AppAccessNotifier::GetAppsAccessingMicrophone() {
   apps::AppRegistryCache* reg_cache = GetActiveUserAppRegistryCache();
   apps::AppCapabilityAccessCache* cap_cache =
       GetActiveUserAppCapabilityAccessCache();
-  // A reg_cache and/or cap_cache of value nullptr is possible if we have
-  // no active user, e.g. the login screen, so we test and return nullopt
-  // in that case instead of using DCHECK().
+  // A reg_cache and/or cap_cache of value nullptr is possible if we have no
+  // active user, e.g. the login screen, so we test and return  empty list in
+  // that case instead of using DCHECK().
   if (!reg_cache || !cap_cache ||
       mic_using_app_ids[active_user_account_id_].empty()) {
-    return absl::nullopt;
+    return {};
   }
 
-  return MapAppIdToShortName(mic_using_app_ids[active_user_account_id_].front(),
-                             cap_cache, reg_cache);
+  std::vector<std::u16string> app_names;
+  for (const auto& app_id : mic_using_app_ids[active_user_account_id_]) {
+    absl::optional<std::u16string> app_name =
+        MapAppIdToShortName(app_id, cap_cache, reg_cache);
+    if (app_name.has_value())
+      app_names.push_back(app_name.value());
+  }
+  return app_names;
 }
 
 void AppAccessNotifier::OnCapabilityAccessUpdate(

chrome/browser/ui/ash/app_access_notifier.h

@@ -8,6 +8,7 @@
 #include <list>
 #include <map>
 #include <string>
+#include <vector>
 
 #include "ash/public/cpp/microphone_mute_notification_delegate.h"
 #include "base/memory/weak_ptr.h"
@@ -45,7 +46,7 @@ class AppAccessNotifier
   ~AppAccessNotifier() override;
 
   // ash::MicrophoneMuteNotificationDelegate
-  absl::optional<std::u16string> GetAppAccessingMicrophone() override;
+  std::vector<std::u16string> GetAppsAccessingMicrophone() override;
 
   // apps::AppCapabilityAccessCache::Observer
   void OnCapabilityAccessUpdate(

chrome/browser/ui/ash/app_access_notifier_unittest.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/ui/ash/app_access_notifier.h"
 
 #include <memory>
+#include <vector>
 
 #include "ash/constants/ash_features.h"
 #include "ash/public/cpp/ash_prefs.h"
@@ -146,8 +147,8 @@ class AppAccessNotifierBaseTest : public testing::Test {
     SetActiveUserAccountId(/*is_primary=*/false);
   }
 
-  absl::optional<std::u16string> GetAppAccessingMicrophone() {
-    return app_access_notifier_->GetAppAccessingMicrophone();
+  std::vector<std::u16string> GetAppsAccessingMicrophone() {
+    return app_access_notifier_->GetAppsAccessingMicrophone();
   }
 
   static apps::AppPtr MakeApp(const std::string app_id,
@@ -289,28 +290,28 @@ INSTANTIATE_TEST_SUITE_P(
     /*IsPrivacyIndicatorsFeatureEnabled()=*/::testing::Bool());
 
 TEST_P(AppAccessNotifierParameterizedTest, NoAppsLaunched) {
-  // Should return a completely value-free app_name.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_FALSE(app_name.has_value());
+  // Should return a empty list of application names.
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_TRUE(app_names.empty());
 }
 
 TEST_P(AppAccessNotifierParameterizedTest, AppLaunchedNotUsingMicrophone) {
   LaunchAppUsingCameraOrMicrophone("id_rose", "name_rose", /*use_camera=*/false,
                                    /*use_microphone=*/false);
 
-  // Should return a completely value-free app_name.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_FALSE(app_name.has_value());
+  // Should return a empty list of application names.
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_TRUE(app_names.empty());
 }
 
 TEST_P(AppAccessNotifierParameterizedTest, AppLaunchedUsingMicrophone) {
   LaunchAppUsingCameraOrMicrophone("id_rose", "name_rose", /*use_camera=*/false,
                                    /*use_microphone=*/true);
 
-  // Should return the name of our app.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_rose");
+  // Returned list of application names should only contain "name_rose".
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_rose");
 }
 
 TEST_P(AppAccessNotifierParameterizedTest,
@@ -324,26 +325,29 @@ TEST_P(AppAccessNotifierParameterizedTest,
   LaunchAppUsingCameraOrMicrophone(
       "id_oscar", "name_oscar", /*use_camera=*/false, /*use_microphone=*/false);
 
-  // Most recently launched mic-using app should be the one we use for the
-  // notification.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_zara");
+  // Most recently launched mic-using app should be in front of the returned
+  // list.
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 3);
+  EXPECT_EQ(app_names[0], u"name_zara");
 
-  // Oscar starts using the mic, Oscar shows up in the notification.
+  // Oscar starts using the mic, Oscar should be the front element of the
+  // returned list now.
   LaunchAppUsingCameraOrMicrophone(
       "id_oscar", "name_oscar", /*use_camera=*/false, /*use_microphone=*/true);
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_oscar");
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 4);
+  EXPECT_EQ(app_names[0], u"name_oscar");
 
-  // If we "kill" Oscar (set to no longer be using the mic or camera),
-  // the notification shows Zara again.
+  // If we "kill" Oscar (set to no longer be using the mic or camera), Oscar
+  // should not be in the returned list anymore. Zara should be at the front.
   LaunchAppUsingCameraOrMicrophone(
       "id_oscar", "name_oscar", /*use_camera=*/false, /*use_microphone=*/false);
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_zara");
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 3);
+  EXPECT_TRUE(std::find(app_names.begin(), app_names.end(), u"name_oscar") ==
+              app_names.end());
+  EXPECT_EQ(app_names[0], u"name_zara");
 }
 
 TEST_P(AppAccessNotifierParameterizedTest, MultipleUsers) {
@@ -358,10 +362,11 @@ TEST_P(AppAccessNotifierParameterizedTest, MultipleUsers) {
                                    /*use_camera=*/false,
                                    /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_primary_user");
+  // App we just launched should be the front and only element of the returned
+  // list.
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_primary_user");
 
   // Secondary user is now the primary user.
   SetActiveUserAccountId(/*is_primary=*/false);
@@ -371,10 +376,11 @@ TEST_P(AppAccessNotifierParameterizedTest, MultipleUsers) {
                                    /*use_camera=*/false,
                                    /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_secondary_user");
+  // App we just launched should be the front and only element of the returned
+  // list.
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_secondary_user");
 
   // Switch back to the primary user and "kill" the app it was running, no app
   // name to show.
@@ -382,23 +388,23 @@ TEST_P(AppAccessNotifierParameterizedTest, MultipleUsers) {
   LaunchAppUsingCameraOrMicrophone("id_primary_user", "name_primary_user",
                                    /*use_camera=*/false,
                                    /*use_microphone=*/false);
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_FALSE(app_name.has_value());
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_TRUE(app_names.empty());
 
   // Now switch back to the secondary user, verify that the same app as before
-  // shows up in the notification.
+  // shows up at the front of the returned list.
   SetActiveUserAccountId(/*is_primary=*/false);
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_secondary_user");
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_secondary_user");
 
   // Now "kill" our secondary user's app and verify that there's no name to
   // show.
   LaunchAppUsingCameraOrMicrophone("id_secondary_user", "name_secondary_user",
                                    /*use_camera=*/false,
                                    /*use_microphone=*/false);
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_FALSE(app_name.has_value());
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_TRUE(app_names.empty());
 }
 
 TEST_P(AppAccessNotifierParameterizedTest, MultipleUsersMultipleApps) {
@@ -413,20 +419,24 @@ TEST_P(AppAccessNotifierParameterizedTest, MultipleUsersMultipleApps) {
                                    /*use_camera=*/false,
                                    /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  absl::optional<std::u16string> app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_primary_user");
+  // App we just launched should be the front and only element of the returned
+  // list.
+  std::vector<std::u16string> app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_primary_user");
 
   // Primary user launches a second mic-using app.
-  LaunchAppUsingCameraOrMicrophone(
-      "id_primary_user", "name_primary_user_another_app", /*use_camera=*/false,
-      /*use_microphone=*/true);
+  LaunchAppUsingCameraOrMicrophone("id_primary_user_another_app",
+                                   "name_primary_user_another_app",
+                                   /*use_camera=*/false,
+                                   /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_primary_user_another_app");
+  // The returned list should contain two application names ordered by most
+  // recently launched.
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 2);
+  EXPECT_EQ(app_names[0], u"name_primary_user_another_app");
+  EXPECT_EQ(app_names[1], u"name_primary_user");
 
   // Secondary user is now the primary user.
   SetActiveUserAccountId(/*is_primary=*/false);
@@ -436,28 +446,33 @@ TEST_P(AppAccessNotifierParameterizedTest, MultipleUsersMultipleApps) {
                                    /*use_camera=*/false,
                                    /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_secondary_user");
+  // App we just launched should be the front and only element of the returned
+  // list.
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 1);
+  EXPECT_EQ(app_names[0], u"name_secondary_user");
 
   // Secondary user launches a second mic-using app.
   LaunchAppUsingCameraOrMicrophone(
-      "id_secondary_user", "name_secondary_user_another_app",
+      "id_secondary_user_another_app", "name_secondary_user_another_app",
       /*use_camera=*/false, /*use_microphone=*/true);
 
-  // App we just launched should show up in the notification.
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_secondary_user_another_app");
+  // The returned list should contain two application names ordered by most
+  // recently launched.
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 2);
+  EXPECT_EQ(app_names[0], u"name_secondary_user_another_app");
+  EXPECT_EQ(app_names[1], u"name_secondary_user");
 
   // Switch back to the primary user.
   SetActiveUserAccountId(/*is_primary=*/true);
 
-  // App we just launched should show up in the notification.
-  app_name = GetAppAccessingMicrophone();
-  EXPECT_TRUE(app_name.has_value());
-  EXPECT_EQ(app_name, u"name_primary_user_another_app");
+  // Both of the apps we launced for the primary user should be in the list
+  // ordered by most recently launched.
+  app_names = GetAppsAccessingMicrophone();
+  EXPECT_EQ((int)app_names.size(), 2);
+  EXPECT_EQ(app_names[0], u"name_primary_user_another_app");
+  EXPECT_EQ(app_names[1], u"name_primary_user");
 }
 
 TEST_P(AppAccessNotifierParameterizedTest, GetShortNameFromAppId) {