mahi: Add mahi educational nudge

Add nudge that educates on the Mahi feature.
https://screenshot.googleplex.com/AeiNKqinXxKruSi

The nudge will show when users visit eligible content, if:
- It hasn't been shown in the past 24 hours
- It has been shown less than three times
- Mahi feature pref is not enabled by the user

Bug: b:319732035
Change-Id: I51d3e53f7c850718c7f48fc4a54c1518b3b7d21f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5602296
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Andre Le <leandre@chromium.org>
Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Victor Vianna <victorvianna@google.com>
Commit-Queue: Kevin Radtke <kradtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1315375}

ash/BUILD.gn

@@ -1892,6 +1892,8 @@ component("ash") {
     "system/mahi/mahi_content_source_button.h",
     "system/mahi/mahi_error_status_view.cc",
     "system/mahi/mahi_error_status_view.h",
+    "system/mahi/mahi_nudge_controller.cc",
+    "system/mahi/mahi_nudge_controller.h",
     "system/mahi/mahi_panel_drag_controller.cc",
     "system/mahi/mahi_panel_drag_controller.h",
     "system/mahi/mahi_panel_view.cc",
@@ -4004,6 +4006,7 @@ test("ash_unittests") {
     "system/lock_screen_notification_controller_unittest.cc",
     "system/magic_boost/magic_boost_disclaimer_view_unittest.cc",
     "system/mahi/mahi_content_source_button_unittest.cc",
+    "system/mahi/mahi_nudge_controller_unittest.cc",
     "system/mahi/mahi_panel_drag_controller_unittest.cc",
     "system/mahi/mahi_panel_view_unittest.cc",
     "system/mahi/mahi_panel_widget_unittest.cc",

ash/ash_prefs.cc

@@ -59,6 +59,7 @@
 #include "ash/system/input_device_settings/keyboard_modifier_metrics_recorder.h"
 #include "ash/system/keyboard_brightness/keyboard_backlight_color_controller.h"
 #include "ash/system/keyboard_brightness/keyboard_brightness_controller.h"
+#include "ash/system/mahi/mahi_nudge_controller.h"
 #include "ash/system/media/media_tray.h"
 #include "ash/system/network/cellular_setup_notifier.h"
 #include "ash/system/network/vpn_detailed_view.h"
@@ -154,6 +155,7 @@ void RegisterProfilePrefs(PrefRegistrySimple* registry,
   KeyboardBacklightColorController::RegisterPrefs(registry);
   KeyboardControllerImpl::RegisterProfilePrefs(registry, country);
   KeyboardModifierMetricsRecorder::RegisterProfilePrefs(registry, for_test);
+  MahiNudgeController::RegisterProfilePrefs(registry);
   MediaControllerImpl::RegisterProfilePrefs(registry);
   MessageCenterController::RegisterProfilePrefs(registry);
   NightLightControllerImpl::RegisterProfilePrefs(registry);

ash/ash_strings.grd

@@ -5288,6 +5288,12 @@ No devices connected.
       <message name="IDS_ASH_MAHI_RETRY_LINK_LABEL_TEXT" desc="Text for the link that user can retry their previous Mahi request">
         Try again
       </message>
+      <message name="IDS_ASH_MAHI_EDUCATIONAL_NUDGE_TITLE" desc="Title for the educational nudge used to discover the Mahi feature">
+        Right-click to summarize
+      </message>
+      <message name="IDS_ASH_MAHI_EDUCATIONAL_NUDGE_BODY" desc="Body for the educational nudge used to discover the Mahi feature">
+        Use Help me read to quickly summarize content or ask questions
+      </message>
 
       <!-- Multi-profiles intro dialog -->
       <message name="IDS_ASH_MULTIPROFILES_INTRO_HEADLINE" desc="Describes which feature multi-profiles intro dialog presents.">

ash/ash_strings_grd/IDS_ASH_MAHI_EDUCATIONAL_NUDGE_BODY.png.sha1

@@ -0,0 +1 @@
+69653e00e3ef602f98f68cd361228fb47a91a19d

ash/ash_strings_grd/IDS_ASH_MAHI_EDUCATIONAL_NUDGE_TITLE.png.sha1

@@ -0,0 +1 @@
+69653e00e3ef602f98f68cd361228fb47a91a19d

ash/constants/ash_pref_names.h

@@ -58,6 +58,12 @@ inline constexpr char kManagedOrcaEnabled[] =
 // A boolean pref of whether mahi is enabled.
 inline constexpr char kMahiEnabled[] = "settings.mahi_enabled";
 
+// An integer pref that stores the times the Mahi nudge has been shown.
+inline constexpr char kMahiNudgeShownCount[] = "mahi.nudge_shown_count";
+
+// A time pref that stores the time the Mahi nudge was last shown.
+inline constexpr char kMahiNudgeLastShownTime[] = "mahi.nudge_last_shown";
+
 // An integer pref which indicates the HMR (Quick answers and Mahi) consent
 // status from the user.
 inline constexpr char kHMRConsentStatus[] = "settings.hmr.consent_status";

ash/constants/notifier_catalogs.h

@@ -245,7 +245,8 @@ enum class NudgeCatalogName {
   kSearchTopRowKeyPressed = 31,
   kSixPackRemappingPressed = 32,
   kCapsLockShortcutPressed = 33,
-  kMaxValue = kCapsLockShortcutPressed
+  kMahi = 34,
+  kMaxValue = kMahi
 };
 
 // A living catalog that registers toasts.

ash/public/cpp/resources/ash_public_unscaled_resources.grd

@@ -63,6 +63,7 @@
       <structure type="lottie" name="IDR_BIRCH_RELEASE_NOTES_ICON" file="unscaled_resources/birch_release_notes_icon.json" compress="gzip" />
       <!-- Mahi -->
       <structure type="lottie" name="IDR_MAHI_GENERAL_ERROR_STATUS_IMAGE" file="unscaled_resources/mahi_general_error_status_image.json" compress="gzip" />
+      <structure type="lottie" name="IDR_MAHI_EDUCATIONAL_NUDGE_IMAGE" file="unscaled_resources/mahi_educational_nudge_image.json" compress="gzip" />
       <!-- Magic Boost -->
       <structure type="lottie" name="IDR_MAGIC_BOOST_DISCLAIMER_ILLUSTRATION" file="unscaled_resources/magic_boost_disclaimer_image.json" compress="gzip" />
       <!-- Shortcut Nudge -->

ash/system/mahi/mahi_constants.h

@@ -5,6 +5,7 @@
 #ifndef ASH_SYSTEM_MAHI_MAHI_CONSTANTS_H_
 #define ASH_SYSTEM_MAHI_MAHI_CONSTANTS_H_
 
+#include "base/time/time.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/views/highlight_border.h"
@@ -73,6 +74,11 @@ inline constexpr int kFakeMahiManagerLoadAnswerDelaySeconds = 3;
 inline constexpr int kFakeMahiManagerLoadSummaryDelaySeconds = 4;
 inline constexpr int kFakeMahiManagerLoadOutlinesDelaySeconds = 6;
 
+// Nudge constants
+inline constexpr char kMahiNudgeId[] = "mahi.nudge";
+inline constexpr base::TimeDelta kNudgeTimeBetweenShown = base::Hours(24);
+inline constexpr int kNudgeMaxShownCount = 3;
+
 // Metrics
 // Contains the types of button existed in Mahi Panel widget. Note: this should
 // be kept in sync with `PanelButton` enum in

ash/system/mahi/mahi_nudge_controller.cc

@@ -0,0 +1,80 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/system/mahi/mahi_nudge_controller.h"
+
+#include "ash/constants/ash_pref_names.h"
+#include "ash/constants/notifier_catalogs.h"
+#include "ash/public/cpp/resources/grit/ash_public_unscaled_resources.h"
+#include "ash/public/cpp/system/anchored_nudge_data.h"
+#include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
+#include "ash/system/mahi/mahi_constants.h"
+#include "ash/system/toast/anchored_nudge_manager_impl.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace ash {
+
+namespace {
+
+PrefService* GetPrefService() {
+  return Shell::Get()->session_controller()->GetActivePrefService();
+}
+
+}  // namespace
+
+MahiNudgeController::MahiNudgeController() = default;
+
+MahiNudgeController::~MahiNudgeController() = default;
+
+// static
+void MahiNudgeController::RegisterProfilePrefs(PrefRegistrySimple* registry) {
+  registry->RegisterIntegerPref(
+      prefs::kMahiNudgeShownCount, 0,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_OS_PREF);
+  registry->RegisterTimePref(prefs::kMahiNudgeLastShownTime, base::Time());
+}
+
+void MahiNudgeController::MaybeShowNudge() {
+  auto* pref_service = GetPrefService();
+
+  // Don't show nudge if the feature has been enabled by the user.
+  if (pref_service->GetBoolean(prefs::kMahiEnabled)) {
+    return;
+  }
+
+  // Nudge has been shown three times. No need to educate anymore.
+  const int shown_count = pref_service->GetInteger(prefs::kMahiNudgeShownCount);
+  if (shown_count >= mahi_constants::kNudgeMaxShownCount) {
+    return;
+  }
+
+  // Don't show nudge if it was shown within the last 24 hours.
+  if (base::Time::Now() -
+          pref_service->GetTime(prefs::kMahiNudgeLastShownTime) <
+      mahi_constants::kNudgeTimeBetweenShown) {
+    return;
+  }
+
+  AnchoredNudgeData nudge_data(
+      mahi_constants::kMahiNudgeId, NudgeCatalogName::kMahi,
+      /*body_text=*/
+      l10n_util::GetStringUTF16(IDS_ASH_MAHI_EDUCATIONAL_NUDGE_BODY));
+  nudge_data.title_text =
+      l10n_util::GetStringUTF16(IDS_ASH_MAHI_EDUCATIONAL_NUDGE_TITLE);
+  nudge_data.image_model =
+      ui::ResourceBundle::GetSharedInstance().GetThemedLottieImageNamed(
+          IDR_MAHI_EDUCATIONAL_NUDGE_IMAGE);
+
+  Shell::Get()->anchored_nudge_manager()->Show(nudge_data);
+
+  // Update nudge prefs.
+  pref_service->SetInteger(prefs::kMahiNudgeShownCount, shown_count + 1);
+  pref_service->SetTime(prefs::kMahiNudgeLastShownTime, base::Time::Now());
+}
+
+}  // namespace ash

ash/system/mahi/mahi_nudge_controller.h

@@ -0,0 +1,31 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_SYSTEM_MAHI_MAHI_NUDGE_CONTROLLER_H_
+#define ASH_SYSTEM_MAHI_MAHI_NUDGE_CONTROLLER_H_
+
+#include "ash/ash_export.h"
+
+class PrefRegistrySimple;
+
+namespace ash {
+
+// Controller for showing the educational nudge for the "Help me read" feature.
+class ASH_EXPORT MahiNudgeController {
+ public:
+  MahiNudgeController();
+  MahiNudgeController(const MahiNudgeController&) = delete;
+  MahiNudgeController& operator=(const MahiNudgeController&) = delete;
+  ~MahiNudgeController();
+
+  static void RegisterProfilePrefs(PrefRegistrySimple* registry);
+
+  // Attempts to show the nudge. The nudge will show if it hasn't been shown in
+  // the past 24 hours, or if it has been shown less than three times.
+  void MaybeShowNudge();
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_MAHI_MAHI_NUDGE_CONTROLLER_H_

ash/system/mahi/mahi_nudge_controller_unittest.cc

@@ -0,0 +1,139 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/system/mahi/mahi_nudge_controller.h"
+
+#include "ash/constants/ash_pref_names.h"
+#include "ash/session/session_controller_impl.h"
+#include "ash/shell.h"
+#include "ash/system/mahi/mahi_constants.h"
+#include "ash/system/toast/anchored_nudge_manager_impl.h"
+#include "ash/test/ash_test_base.h"
+#include "base/time/time.h"
+#include "base/time/time_override.h"
+#include "components/prefs/pref_service.h"
+#include "ui/lottie/resource.h"
+
+namespace ash {
+
+namespace {
+
+void SetMahiEnabledByUserPref(bool enabled) {
+  Shell::Get()->session_controller()->GetActivePrefService()->SetBoolean(
+      ash::prefs::kMahiEnabled, enabled);
+}
+
+bool IsMahiNudgeShown() {
+  return Shell::Get()->anchored_nudge_manager()->IsNudgeShown(
+      mahi_constants::kMahiNudgeId);
+}
+
+}  // namespace
+
+class MahiNudgeControllerTest : public AshTestBase {
+ public:
+  MahiNudgeControllerTest() {
+    mahi_nudge_controller_ = std::make_unique<MahiNudgeController>();
+
+    // Sets the default functions for the test to create image with the lottie
+    // resource id. Otherwise there's no `g_parse_lottie_as_still_image_` set in
+    // the `ResourceBundle`.
+    ui::ResourceBundle::SetLottieParsingFunctions(
+        &lottie::ParseLottieAsStillImage,
+        &lottie::ParseLottieAsThemedStillImage);
+  }
+
+  MahiNudgeController* nudge_controller() {
+    return mahi_nudge_controller_.get();
+  }
+
+  AnchoredNudgeManagerImpl* nudge_manager() {
+    return Shell::Get()->anchored_nudge_manager();
+  }
+
+  static base::Time GetTestTime() { return test_time_; }
+  static void SetTestTime(base::Time test_time) { test_time_ = test_time; }
+
+ private:
+  std::unique_ptr<MahiNudgeController> mahi_nudge_controller_;
+  static inline base::Time test_time_;
+};
+
+// Tests that the nudge can show when the user is not opted into Mahi.
+TEST_F(MahiNudgeControllerTest, NudgeShows_WhenUserPrefNotEnabled) {
+  SetMahiEnabledByUserPref(false);
+
+  EXPECT_FALSE(IsMahiNudgeShown());
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_TRUE(IsMahiNudgeShown());
+}
+
+// Tests that the nudge won't show when the user has opted into Mahi.
+TEST_F(MahiNudgeControllerTest, NudgeDoesNotShow_WhenUserPrefEnabled) {
+  SetMahiEnabledByUserPref(true);
+
+  EXPECT_FALSE(IsMahiNudgeShown());
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_FALSE(IsMahiNudgeShown());
+}
+
+// Tests that the nudge won't show if the time between shown threshold hasn't
+// passed since it was last shown.
+TEST_F(MahiNudgeControllerTest, NudgeDoesNotShow_IfRecentlyShown) {
+  SetMahiEnabledByUserPref(false);
+
+  SetTestTime(base::Time::Now());
+  base::subtle::ScopedTimeClockOverrides clock_override(
+      /*time_override=*/&MahiNudgeControllerTest::GetTestTime,
+      /*time_ticks_override=*/nullptr, /*thread_ticks_override=*/nullptr);
+
+  // Show the nudge once and close it.
+  EXPECT_FALSE(IsMahiNudgeShown());
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_TRUE(IsMahiNudgeShown());
+  nudge_manager()->Cancel(mahi_constants::kMahiNudgeId);
+
+  // Attempt showing the nudge again immediately. It should not show.
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_FALSE(IsMahiNudgeShown());
+
+  // Attempt showing the nudge after some time but before its threshold time has
+  // fully passed. It should not show.
+  SetTestTime(GetTestTime() + mahi_constants::kNudgeTimeBetweenShown -
+              base::Hours(1));
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_FALSE(IsMahiNudgeShown());
+
+  // Attempt showing the nudge after its "time between shown" threshold has
+  // passed. It should show.
+  SetTestTime(GetTestTime() + mahi_constants::kNudgeTimeBetweenShown +
+              base::Hours(1));
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_TRUE(IsMahiNudgeShown());
+}
+
+// Tests that the nudge won't show if it has been shown its max number of times.
+TEST_F(MahiNudgeControllerTest, NudgeDoesNotShow_IfMaxTimesShown) {
+  SetMahiEnabledByUserPref(false);
+
+  SetTestTime(base::Time::Now());
+  base::subtle::ScopedTimeClockOverrides clock_override(
+      /*time_override=*/&MahiNudgeControllerTest::GetTestTime,
+      /*time_ticks_override=*/nullptr, /*thread_ticks_override=*/nullptr);
+
+  // Show the nudge its max number of times.
+  for (int i = 0; i < mahi_constants::kNudgeMaxShownCount; i++) {
+    nudge_controller()->MaybeShowNudge();
+    EXPECT_TRUE(IsMahiNudgeShown());
+    nudge_manager()->Cancel(mahi_constants::kMahiNudgeId);
+    SetTestTime(GetTestTime() + mahi_constants::kNudgeTimeBetweenShown +
+                base::Hours(1));
+  }
+
+  // Attempt showing the nudge once more. It should not show.
+  nudge_controller()->MaybeShowNudge();
+  EXPECT_FALSE(IsMahiNudgeShown());
+}
+
+}  // namespace ash

chrome/browser/ash/mahi/mahi_manager_impl.cc

@@ -13,6 +13,7 @@
 
 #include "ash/constants/ash_pref_names.h"
 #include "ash/shell.h"
+#include "ash/system/mahi/mahi_nudge_controller.h"
 #include "ash/system/mahi/mahi_ui_controller.h"
 #include "ash/webui/settings/public/constants/routes.mojom.h"
 #include "ash/webui/settings/public/constants/setting.mojom.h"
@@ -108,7 +109,8 @@ std::unique_ptr<manta::MahiProvider> CreateProvider() {
 namespace ash {
 
 MahiManagerImpl::MahiManagerImpl()
-    : cache_manager_(std::make_unique<MahiCacheManager>()) {
+    : cache_manager_(std::make_unique<MahiCacheManager>()),
+      mahi_nudge_controller_(std::make_unique<MahiNudgeController>()) {
   session_observation_.Observe(Shell::Get()->session_controller());
   PrefService* last_active_user_pref_service =
       Shell::Get()->session_controller()->GetLastActiveUserPrefService();
@@ -435,6 +437,11 @@ void MahiManagerImpl::NotifyRefreshAvailability(bool available) {
   if (ui_controller_.IsMahiPanelOpen()) {
     ui_controller_.NotifyRefreshAvailabilityChanged(available);
   }
+
+  // Attempt showing an educational nudge when users visit eligible content.
+  if (available) {
+    mahi_nudge_controller_->MaybeShowNudge();
+  }
 }
 
 void MahiManagerImpl::OnActiveUserPrefServiceChanged(

chrome/browser/ash/mahi/mahi_manager_impl.h

@@ -23,6 +23,8 @@
 
 namespace ash {
 
+class MahiNudgeController;
+
 // Implementation of `MahiManager`.
 class MahiManagerImpl : public chromeos::MahiManager, public SessionObserver {
  public:
@@ -54,8 +56,7 @@ class MahiManagerImpl : public chromeos::MahiManager, public SessionObserver {
       const base::UnguessableToken media_app_client_id) override;
   std::optional<base::UnguessableToken> GetMediaAppPDFClientId() const override;
 
-  // Notifies the panel that refresh is available or not for the corresponding
-  // surface.
+  // Called when availability for a refresh changes based on the shown content.
   void NotifyRefreshAvailability(bool available);
 
   // SessionObserver:
@@ -128,6 +129,8 @@ class MahiManagerImpl : public chromeos::MahiManager, public SessionObserver {
 
   std::unique_ptr<MahiCacheManager> cache_manager_;
 
+  std::unique_ptr<MahiNudgeController> mahi_nudge_controller_;
+
   // If true, tries to get content from MediaAppContentManager instead.
   bool media_app_pdf_focused_ = false;
   base::UnguessableToken media_app_client_id_;

chrome/browser/ash/mahi/mahi_manager_impl_unittest.cc

@@ -10,6 +10,8 @@
 #include "ash/constants/ash_pref_names.h"
 #include "ash/constants/ash_switches.h"
 #include "ash/shell.h"
+#include "ash/system/mahi/mahi_constants.h"
+#include "ash/system/toast/anchored_nudge_manager_impl.h"
 #include "ash/test/ash_test_base.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ -29,9 +31,11 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/image/image_skia.h"
+#include "ui/lottie/resource.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
+
 using ::testing::IsNull;
 
 constexpr char kFakeSummary[] = "Fake summary";
@@ -56,6 +60,12 @@ class FakeMahiProvider : public manta::MahiProvider {
  private:
   int num_summarize_call_ = 0;
 };
+
+bool IsMahiNudgeShown() {
+  return ash::Shell::Get()->anchored_nudge_manager()->IsNudgeShown(
+      ash::mahi_constants::kMahiNudgeId);
+}
+
 }  // namespace
 
 namespace ash {
@@ -64,7 +74,14 @@ class MahiManagerImplTest : public NoSessionAshTestBase {
  public:
   MahiManagerImplTest()
       : NoSessionAshTestBase(
-            base::test::TaskEnvironment::TimeSource::MOCK_TIME) {}
+            base::test::TaskEnvironment::TimeSource::MOCK_TIME) {
+    // Sets the default functions for the test to create image with the lottie
+    // resource id. Otherwise there's no `g_parse_lottie_as_still_image_` set in
+    // the `ResourceBundle`.
+    ui::ResourceBundle::SetLottieParsingFunctions(
+        &lottie::ParseLottieAsStillImage,
+        &lottie::ParseLottieAsThemedStillImage);
+  }
 
   MahiManagerImplTest(const MahiManagerImplTest&) = delete;
   MahiManagerImplTest& operator=(const MahiManagerImplTest&) = delete;
@@ -90,7 +107,7 @@ class MahiManagerImplTest : public NoSessionAshTestBase {
     NoSessionAshTestBase::TearDown();
   }
 
-  void SetUserPref(bool enabled) {
+  void SetMahiEnabledByUserPref(bool enabled) {
     Shell::Get()->session_controller()->GetActivePrefService()->SetBoolean(
         ash::prefs::kMahiEnabled, enabled);
   }
@@ -115,6 +132,10 @@ class MahiManagerImplTest : public NoSessionAshTestBase {
     return mahi_manager_impl_->cache_manager_.get();
   }
 
+  void NotifyRefreshAvailability(bool available) {
+    mahi_manager_impl_->NotifyRefreshAvailability(available);
+  }
+
   void RequestSummary() {
     // Sets the page that needed to get summary.
     mahi_manager_impl_->SetCurrentFocusedPageInfo(
@@ -185,7 +206,7 @@ TEST_F(MahiManagerImplTest, TurnOffSettingsClearCache) {
   EXPECT_EQ(GetCacheManager()->size(), 1);
 
   // Cache must be empty after user turn off the settings.
-  SetUserPref(false);
+  SetMahiEnabledByUserPref(false);
   EXPECT_EQ(GetCacheManager()->size(), 0);
 }
 
@@ -194,14 +215,14 @@ TEST_F(MahiManagerImplTest, SetMahiPrefOnLogin) {
   // true or false.
   for (bool mahi_enabled : {false, true}) {
     // Sets the pref for the default user.
-    SetUserPref(mahi_enabled);
+    SetMahiEnabledByUserPref(mahi_enabled);
     ASSERT_EQ(IsEnabled(), mahi_enabled);
     const AccountId user1_account_id =
         Shell::Get()->session_controller()->GetActiveAccountId();
 
     // Sets the pref for the second user.
     SimulateUserLogin("other@user.test");
-    SetUserPref(!mahi_enabled);
+    SetMahiEnabledByUserPref(!mahi_enabled);
     EXPECT_EQ(IsEnabled(), !mahi_enabled);
 
     // Switching back to the previous user will update to correct pref.
@@ -216,11 +237,31 @@ TEST_F(MahiManagerImplTest, SetMahiPrefOnLogin) {
 
 TEST_F(MahiManagerImplTest, OnPreferenceChanged) {
   for (bool mahi_enabled : {false, true, false}) {
-    SetUserPref(mahi_enabled);
+    SetMahiEnabledByUserPref(mahi_enabled);
     EXPECT_EQ(IsEnabled(), mahi_enabled);
   }
 }
 
+// Tests that the Mahi educational nudge is shown when the user visits eligible
+// content and they have not opted in to the feature.
+TEST_F(MahiManagerImplTest, ShowEducationalNudge) {
+  SetMahiEnabledByUserPref(false);
+
+  EXPECT_FALSE(IsMahiNudgeShown());
+
+  // Notifying that a refresh is not available should have no effect.
+  NotifyRefreshAvailability(/*available=*/false);
+  EXPECT_FALSE(IsMahiNudgeShown());
+
+  // Notifying that a refresh is available should show the nudge.
+  NotifyRefreshAvailability(/*available=*/true);
+  EXPECT_TRUE(IsMahiNudgeShown());
+
+  // Notifying that a refresh is not available should have no effect.
+  NotifyRefreshAvailability(/*available=*/false);
+  EXPECT_TRUE(IsMahiNudgeShown());
+}
+
 class MahiManagerImplFeatureKeyTest : public NoSessionAshTestBase {
  public:
   MahiManagerImplFeatureKeyTest() {

chrome/browser/sync/prefs/chrome_syncable_prefs_database.cc

@@ -350,6 +350,7 @@ enum {
   kDesktopToiOSAddressPromoLastImpressionTimestamp = 100291,
   kDesktopToiOSAddressPromoImpressionsCounter = 100292,
   kDesktopToiOSAddressPromoOptOut = 100293,
+  kMahiNudgeShownCount = 100294,
   // See components/sync_preferences/README.md about adding new entries here.
   // vvvvv IMPORTANT! vvvvv
   // Note to the reviewer: IT IS YOUR RESPONSIBILITY to ensure that new syncable
@@ -1177,6 +1178,10 @@ constexpr auto kChromeSyncablePrefsAllowlist = base::MakeFixedFlatMap<
      {syncable_prefs_ids::kShelfMallAppPinRolls, syncer::OS_PREFERENCES,
       sync_preferences::PrefSensitivity::kNone,
       sync_preferences::MergeBehavior::kMergeableListWithRewriteOnUpdate}},
+    {ash::prefs::kMahiNudgeShownCount,
+     {syncable_prefs_ids::kMahiNudgeShownCount, syncer::OS_PREFERENCES,
+      sync_preferences::PrefSensitivity::kNone,
+      sync_preferences::MergeBehavior::kNone}},
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
     {performance_manager::user_tuning::prefs::kTabDiscardingExceptions,
      {syncable_prefs_ids::kTabDiscardingExceptions, syncer::PREFERENCES,

tools/metrics/histograms/metadata/sync/enums.xml

@@ -620,6 +620,7 @@ chromium-metrics-reviews@google.com.
   <int value="100291" label="iOSAddressPromoLastImpressionTimestamp"/>
   <int value="100292" label="iOSAddressPromoImpressionsCounter"/>
   <int value="100293" label="iOSAddressPromoOptOut"/>
+  <int value="100294" label="MahiNudgeShownCount"/>
 <!-- LINT.ThenChange(/chrome/browser/sync/prefs/chrome_syncable_prefs_database.cc:ChromeSyncablePref)-->
 
 <!-- LINT.IfChange(IosSyncablePref) -->