From 2e421e49757bf4231412a3f46d756df41df71272 Mon Sep 17 00:00:00 2001
From: Nicolas Dossou-Gbete <dgn@chromium.org>
Date: Fri, 03 Jul 2026 09:21:44 -0700
Subject: [PATCH] Reland "Avoid propagating extension or policy choice across profiles"

This is a reland of commit 1c6acb95514ada701e107ff963b8689281503d71

Fixes the test-specific compilation failure in ChromeForTesting builds,
un-guarding one of the test helper functions that the new tests start
using in CFT builds.

Original change's description:
> Avoid propagating extension or policy choice across profiles
>
> When capturing default search engine (DSE) choice data to propagate to
> forked profiles, skip the propagation for the cases where the active DSE
> is not set by the user (e.g. managed by extension or policies, or
> fallback)
>
> Adds the dedicated UMA histogram
> `Search.ChoiceDebug.PropagatedDataOutcome` to track the impact of this
> change.
>
> Bug: 513607252
> Change-Id: I86c1fdfb6cbe392e4cd7bb8d48dc179f5b07fcd8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7986107
> Commit-Queue: Nicolas Dossou-Gbété <dgn@chromium.org>
> Reviewed-by: David Roger <droger@chromium.org>
> Reviewed-by: James Lee <ljjlee@google.com>
> Auto-Submit: Nicolas Dossou-Gbété <dgn@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1656537}

Bug: 513607252
Change-Id: I1b6cb0ec5fef5d6a1960ffb876a15064febad439
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8034248
Reviewed-by: James Lee <ljjlee@google.com>
Auto-Submit: Nicolas Dossou-Gbété <dgn@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1656620}
---

diff --git a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.cc b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.cc
index ad63ef3f..072359d2 100644
--- a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.cc
+++ b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.cc
@@ -292,49 +292,82 @@
 }
 
 // static
-search_engines::ChoiceData
+std::optional<search_engines::ChoiceData>
 SearchEngineChoiceDialogService::GetChoiceDataFromProfile(Profile& profile) {
   PrefService* pref_service = profile.GetPrefs();
   TemplateURLService* template_url_service =
       TemplateURLServiceFactory::GetForProfile(&profile);
   CHECK(template_url_service);
+
+  switch (template_url_service->default_search_provider_source()) {
+    case DefaultSearchManager::FROM_FALLBACK:
+      base::UmaHistogramEnumeration(
+          "Search.ChoiceDebug.PropagatedDataOutcome",
+          CurrentDefaultPropagationOutcome::kSkippedIsFallback);
+      return std::nullopt;
+
+    case DefaultSearchManager::FROM_EXTENSION:
+      base::UmaHistogramEnumeration(
+          "Search.ChoiceDebug.PropagatedDataOutcome",
+          CurrentDefaultPropagationOutcome::kSkippedIsExtension);
+      return std::nullopt;
+
+    case DefaultSearchManager::FROM_POLICY:
+    case DefaultSearchManager::FROM_POLICY_RECOMMENDED:
+      base::UmaHistogramEnumeration(
+          "Search.ChoiceDebug.PropagatedDataOutcome",
+          CurrentDefaultPropagationOutcome::kSkippedDueToPolicies);
+      return std::nullopt;
+
+    case DefaultSearchManager::FROM_USER:
+      break;  // Current default eligible for propagation.
+  }
+
+  CHECK(template_url_service->GetDefaultSearchProvider());
   const TemplateURLData& default_search_engine =
       template_url_service->GetDefaultSearchProvider()->data();
 
-  return {.timestamp = pref_service->GetInt64(
-              prefs::kDefaultSearchProviderChoiceScreenCompletionTimestamp),
-          .chrome_version = pref_service->GetString(
-              prefs::kDefaultSearchProviderChoiceScreenCompletionVersion),
-          .default_search_engine = default_search_engine};
+  base::UmaHistogramEnumeration(
+      "Search.ChoiceDebug.PropagatedDataOutcome",
+      CurrentDefaultPropagationOutcome::kPropagatedCurrentDefault);
+
+  return search_engines::ChoiceData{
+      .timestamp = pref_service->GetInt64(
+          prefs::kDefaultSearchProviderChoiceScreenCompletionTimestamp),
+      .chrome_version = pref_service->GetString(
+          prefs::kDefaultSearchProviderChoiceScreenCompletionVersion),
+      .default_search_engine = default_search_engine};
 }
 
 // static
 void SearchEngineChoiceDialogService::UpdateProfileFromChoiceData(
     Profile& profile,
-    const search_engines::ChoiceData& choice_data) {
-  PrefService* pref_service = profile.GetPrefs();
-  if (choice_data.timestamp != 0) {
-    pref_service->SetInt64(
-        prefs::kDefaultSearchProviderChoiceScreenCompletionTimestamp,
-        choice_data.timestamp);
-  }
-
-  if (!choice_data.chrome_version.empty()) {
-    pref_service->SetString(
-        prefs::kDefaultSearchProviderChoiceScreenCompletionVersion,
-        choice_data.chrome_version);
+    const std::optional<search_engines::ChoiceData>& choice_data) {
+  if (!choice_data.has_value()) {
+    return;
   }
 
   const TemplateURLData& default_search_engine =
-      choice_data.default_search_engine;
-  if (!default_search_engine.keyword().empty() &&
-      !default_search_engine.url().empty()) {
-    TemplateURLService* template_url_service =
-        TemplateURLServiceFactory::GetForProfile(&profile);
-    CHECK(template_url_service);
-    TemplateURL template_url(default_search_engine);
-    template_url_service->SetUserSelectedDefaultSearchProvider(&template_url);
+      choice_data->default_search_engine;
+
+  PrefService* pref_service = profile.GetPrefs();
+  if (choice_data->timestamp != 0) {
+    pref_service->SetInt64(
+        prefs::kDefaultSearchProviderChoiceScreenCompletionTimestamp,
+        choice_data->timestamp);
   }
+
+  if (!choice_data->chrome_version.empty()) {
+    pref_service->SetString(
+        prefs::kDefaultSearchProviderChoiceScreenCompletionVersion,
+        choice_data->chrome_version);
+  }
+
+  TemplateURLService* template_url_service =
+      TemplateURLServiceFactory::GetForProfile(&profile);
+  CHECK(template_url_service);
+  TemplateURL template_url(default_search_engine);
+  template_url_service->SetUserSelectedDefaultSearchProvider(&template_url);
 }
 
 TemplateURL::TemplateURLVector
diff --git a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.h b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.h
index 6b83b61..9b9a9482 100644
--- a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.h
+++ b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service.h
@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_SEARCH_ENGINE_CHOICE_SEARCH_ENGINE_CHOICE_DIALOG_SERVICE_H_
 #define CHROME_BROWSER_SEARCH_ENGINE_CHOICE_SEARCH_ENGINE_CHOICE_DIALOG_SERVICE_H_
 
+#include <optional>
 #include <string>
 
 #include "base/containers/flat_map.h"
@@ -152,12 +153,28 @@
   static void SetDialogDisabledForTests(bool dialog_disabled);
 
   // Returns a copy of the `ChoiceData` specific to `profile`.
-  static search_engines::ChoiceData GetChoiceDataFromProfile(Profile& profile);
+  // LINT.IfChange(CurrentDefaultPropagationOutcome)
+  enum class CurrentDefaultPropagationOutcome {
+    kPropagatedCurrentDefault = 0,
+    kSkippedDueToPolicies = 1,
+    kSkippedIsFallback = 2,
+    kSkippedIsExtension = 3,
+    kMaxValue = kSkippedIsExtension,
+  };
+  // LINT.ThenChange(/tools/metrics/histograms/metadata/search/enums.xml:CurrentDefaultPropagationOutcome)
+
+  // Returns a copy of the `ChoiceData` specific to `profile`, or `std::nullopt`
+  // if there is no default search engine to propagate. This function ignores
+  // any extension-provided default search engine to capture the underlying user
+  // choice (or system default), and skips propagation entirely if the default
+  // search is managed by an enterprise policy.
+  static std::optional<search_engines::ChoiceData> GetChoiceDataFromProfile(
+      Profile& profile);
 
   // Updates `profile` with the values from `choice_data`.
   static void UpdateProfileFromChoiceData(
       Profile& profile,
-      const search_engines::ChoiceData& choice_data);
+      const std::optional<search_engines::ChoiceData>& choice_data);
 
  private:
   friend class SearchEngineChoiceDialogServiceFactory;
diff --git a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc
index c24152a..bf9330a5 100644

diff --git a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc
index c24152a..bf9330a5 100644
--- a/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc
+++ b/chrome/browser/search_engine_choice/search_engine_choice_dialog_service_unittest.cc
@@ -19,6 +19,7 @@
 #include "chrome/browser/search_engine_choice/search_engine_choice_service_factory.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/common/webui_url_constants.h"
+#include "chrome/test/base/search_test_utils.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile_manager.h"
 #include "components/country_codes/country_codes.h"
@@ -31,9 +32,11 @@
 #include "components/search_engines/search_engines_pref_names.h"
 #include "components/search_engines/search_engines_switches.h"
 #include "components/search_engines/search_engines_test_util.h"
+#include "components/search_engines/template_url_data_util.h"
 #include "components/search_engines/template_url_prepopulate_data.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/signin/public/base/signin_switches.h"
+#include "components/sync_preferences/testing_pref_service_syncable.h"
 #include "content/public/test/browser_task_environment.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -63,7 +66,6 @@
 
 constexpr CountryId kBelgiumCountryId("BE");
 
-#if !BUILDFLAG(CHROME_FOR_TESTING)
 void SetUserSelectedDefaultSearchProvider(
     TemplateURLService* template_url_service,
     bool created_by_policy) {
@@ -89,6 +91,7 @@
   template_url_service->SetUserSelectedDefaultSearchProvider(template_url);
 }
 
+#if !BUILDFLAG(CHROME_FOR_TESTING)
 struct TestParam {
   std::string test_suffix;
   std::optional<regional_capabilities::SearchEngineCountryListOverride>
@@ -549,3 +552,141 @@
   ASSERT_EQ(search_engine_choice_dialog_service, nullptr);
 }
 #endif  // !BUILDFLAG(CHROME_FOR_TESTING)
+
+TEST_F(SearchEngineChoiceDialogServiceTest,
+       GetChoiceDataFromProfilePropagatesCurrentDefault) {
+  base::HistogramTester histogram_tester;
+  TemplateURLService* source_template_url_service =
+      TemplateURLServiceFactory::GetForProfile(profile());
+  search_test_utils::WaitForTemplateURLServiceToLoad(
+      source_template_url_service);
+
+  // Set a user-selected default search provider to ensure the source is
+  // FROM_USER.
+  SetUserSelectedDefaultSearchProvider(source_template_url_service,
+                                       /*created_by_policy=*/false);
+
+  const TemplateURL* underlying_default =
+      source_template_url_service->GetDefaultSearchProvider();
+  ASSERT_TRUE(underlying_default);
+  const std::string underlying_default_url = underlying_default->url();
+
+  std::optional<search_engines::ChoiceData> choice_data =
+      SearchEngineChoiceDialogService::GetChoiceDataFromProfile(*profile());
+  ASSERT_TRUE(choice_data.has_value());
+  EXPECT_EQ(choice_data->default_search_engine.url(), underlying_default_url);
+
+  histogram_tester.ExpectUniqueSample(
+      "Search.ChoiceDebug.PropagatedDataOutcome",
+      SearchEngineChoiceDialogService::CurrentDefaultPropagationOutcome::
+          kPropagatedCurrentDefault,
+      1);
+}
+
+TEST_F(SearchEngineChoiceDialogServiceTest,
+       GetChoiceDataFromProfileIgnoresExtensionProvidedDefault) {
+  base::HistogramTester histogram_tester;
+  TemplateURLService* source_template_url_service =
+      TemplateURLServiceFactory::GetForProfile(profile());
+  search_test_utils::WaitForTemplateURLServiceToLoad(
+      source_template_url_service);
+
+  // Install an extension-provided default search engine in the source profile.
+  std::unique_ptr<TemplateURLData> extension_data =
+      GenerateDummyTemplateURLData("extension");
+  source_template_url_service->Add(std::make_unique<TemplateURL>(
+      *extension_data, TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION,
+      "extension_id", base::Time(), /*wants_to_be_default_engine=*/true));
+  SetExtensionDefaultSearchInPrefs(profile()->GetTestingPrefService(),
+                                   *extension_data);
+  ASSERT_TRUE(
+      source_template_url_service->IsExtensionControlledDefaultSearch());
+
+  // The choice data captured for propagation to a new profile should be absent
+  // for extensions under the new logic.
+  std::optional<search_engines::ChoiceData> choice_data =
+      SearchEngineChoiceDialogService::GetChoiceDataFromProfile(*profile());
+  EXPECT_EQ(choice_data, std::nullopt);
+
+  histogram_tester.ExpectUniqueSample(
+      "Search.ChoiceDebug.PropagatedDataOutcome",
+      SearchEngineChoiceDialogService::CurrentDefaultPropagationOutcome::
+          kSkippedIsExtension,
+      1);
+
+  // Propagating absent choice data should leave the destination profile's
+  // default search engine unchanged from its own default.
+  TestingProfile* destination_profile =
+      profile_manager()->CreateTestingProfile("Profile 2");
+  TemplateURLServiceFactory::GetInstance()->SetTestingFactory(
+      destination_profile,
+      base::BindRepeating(&TemplateURLServiceFactory::BuildInstanceFor));
+  TemplateURLService* destination_template_url_service =
+      TemplateURLServiceFactory::GetForProfile(destination_profile);
+  search_test_utils::WaitForTemplateURLServiceToLoad(
+      destination_template_url_service);
+
+  const std::string destination_default_url =
+      destination_template_url_service->GetDefaultSearchProvider()->url();
+
+  SearchEngineChoiceDialogService::UpdateProfileFromChoiceData(
+      *destination_profile, choice_data);
+  EXPECT_FALSE(
+      destination_template_url_service->IsExtensionControlledDefaultSearch());
+  EXPECT_EQ(destination_template_url_service->GetDefaultSearchProvider()->url(),
+            destination_default_url);
+}
+
+TEST_F(SearchEngineChoiceDialogServiceTest,
+       GetChoiceDataFromProfileSkipsIfNoUnderlyingDefault) {
+  base::HistogramTester histogram_tester;
+  TemplateURLService* source_template_url_service =
+      TemplateURLServiceFactory::GetForProfile(profile());
+  search_test_utils::WaitForTemplateURLServiceToLoad(
+      source_template_url_service);
+
+  // When no user choice is made, a fresh profile uses the fallback search
+  // engine, which skips under the new FROM_FALLBACK policy.
+  std::optional<search_engines::ChoiceData> choice_data =
+      SearchEngineChoiceDialogService::GetChoiceDataFromProfile(*profile());
+  EXPECT_EQ(choice_data, std::nullopt);
+
+  histogram_tester.ExpectUniqueSample(
+      "Search.ChoiceDebug.PropagatedDataOutcome",
+      SearchEngineChoiceDialogService::CurrentDefaultPropagationOutcome::
+          kSkippedIsFallback,
+      1);
+}
+
+TEST_F(SearchEngineChoiceDialogServiceTest,
+       GetChoiceDataFromProfileSkipsIfManagedByPolicy) {
+  base::HistogramTester histogram_tester;
+  TemplateURLService* source_template_url_service =
+      TemplateURLServiceFactory::GetForProfile(profile());
+  search_test_utils::WaitForTemplateURLServiceToLoad(
+      source_template_url_service);
+
+  TemplateURLData data;
+  data.SetShortName(u"policy");
+  data.SetKeyword(u"policy");
+  data.SetURL("https://policy/url?bar={searchTerms}");
+  profile()->GetTestingPrefService()->SetManagedPref(
+      DefaultSearchManager::kDefaultSearchProviderDataPrefName,
+      TemplateURLDataToDictionary(data));
+
+  ASSERT_TRUE(source_template_url_service->is_default_search_managed());
+
+  std::optional<search_engines::ChoiceData> choice_data =
+      SearchEngineChoiceDialogService::GetChoiceDataFromProfile(*profile());
+  EXPECT_EQ(choice_data, std::nullopt);
+
+  histogram_tester.ExpectUniqueSample(
+      "Search.ChoiceDebug.PropagatedDataOutcome",
+      SearchEngineChoiceDialogService::CurrentDefaultPropagationOutcome::
+          kSkippedDueToPolicies,
+      1);
+
+  // Clear for subsequent tests.
+  profile()->GetTestingPrefService()->RemoveManagedPref(
+      DefaultSearchManager::kDefaultSearchProviderDataPrefName);
+}