Make default password store configurable via a feature param

This adds a new feature param (and corresponding about:flags entry)
which, when set to true, makes the profile store the default one for
new users.

Bug: 1160655
Change-Id: I549b624fdc4cf3f01fdfb0425cc12299d58ed9aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2599529
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842060}

chrome/browser/about_flags.cc

@@ -2497,6 +2497,16 @@ constexpr FeatureEntry::FeatureVariation
          kPlatformProvidedTrustTokenIssuance,
          base::size(kPlatformProvidedTrustTokenIssuance), nullptr}};
 
+const FeatureEntry::FeatureParam kPasswordsAccountStorage_ProfileStore[] = {
+    {password_manager::features::kSaveToProfileStoreByDefault, "true"},
+};
+
+const FeatureEntry::FeatureVariation kPasswordsAccountStorageVariations[] = {
+    {"(save to profile store by default)",
+     kPasswordsAccountStorage_ProfileStore,
+     base::size(kPasswordsAccountStorage_ProfileStore), nullptr},
+};
+
 // RECORDING USER METRICS FOR FLAGS:
 // -----------------------------------------------------------------------------
 // The first line of the entry is the internal name.
@@ -5996,8 +6006,10 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kEnablePasswordsAccountStorageName,
      flag_descriptions::kEnablePasswordsAccountStorageDescription,
      kOsWin | kOsMac | kOsLinux,
-     FEATURE_VALUE_TYPE(
-         password_manager::features::kEnablePasswordsAccountStorage)},
+     FEATURE_WITH_PARAMS_VALUE_TYPE(
+         password_manager::features::kEnablePasswordsAccountStorage,
+         kPasswordsAccountStorageVariations,
+         "ButterForPasswords")},
 
 #if defined(OS_WIN) || defined(OS_MAC) || defined(OS_LINUX) || \
     defined(OS_CHROMEOS)

components/password_manager/core/browser/password_manager_features_util.cc

@@ -327,9 +327,17 @@ PasswordForm::Store GetDefaultPasswordStore(
           .GetDefaultStore();
   // If none of the early-outs above triggered, then we *can* save to the
   // account store in principle (though the user might not have opted in to that
-  // yet). In this case, default to the account store.
-  if (default_store == PasswordForm::Store::kNotSet)
-    return PasswordForm::Store::kAccountStore;
+  // yet).
+  if (default_store == PasswordForm::Store::kNotSet) {
+    // If the user hasn't made a choice about the default store yet, retrieve it
+    // from a feature param.
+    bool save_to_profile_store = base::GetFieldTrialParamByFeatureAsBool(
+        features::kEnablePasswordsAccountStorage,
+        features::kSaveToProfileStoreByDefault,
+        features::kSaveToProfileStoreByDefaultDefaultValue);
+    return save_to_profile_store ? PasswordForm::Store::kProfileStore
+                                 : PasswordForm::Store::kAccountStore;
+  }
   return default_store;
 }
 

components/password_manager/core/browser/password_manager_features_util_unittest.cc

@@ -258,6 +258,39 @@ TEST(PasswordFeatureManagerUtil, AccountStoragePerAccountSettings) {
             PasswordForm::Store::kProfileStore);
 }
 
+TEST(PasswordFeatureManagerUtil, SaveToProfileStoreByDefaultParam) {
+  base::test::ScopedFeatureList features;
+  features.InitAndEnableFeatureWithParameters(
+      features::kEnablePasswordsAccountStorage,
+      {{features::kSaveToProfileStoreByDefault, "true"}});
+
+  TestingPrefServiceSimple pref_service;
+  pref_service.registry()->RegisterDictionaryPref(
+      prefs::kAccountStoragePerAccountSettings);
+
+  CoreAccountInfo account;
+  account.email = "name@account.com";
+  account.gaia = "name";
+  account.account_id = CoreAccountId::FromGaiaId(account.gaia);
+
+  // SyncService is running in transport mode.
+  syncer::TestSyncService sync_service;
+  sync_service.SetAuthenticatedAccountInfo(account);
+  sync_service.SetIsAuthenticatedAccountPrimary(false);
+  sync_service.SetDisableReasons({});
+  sync_service.SetTransportState(syncer::SyncService::TransportState::ACTIVE);
+  ASSERT_FALSE(sync_service.IsSyncFeatureEnabled());
+
+  // By default, the user is not opted in. Since the
+  // |kSaveToProfileStoreByDefault| parameter is set, the default store should
+  // be the *profile* one. The opt-in for the account store should still show
+  // up, though.
+  ASSERT_FALSE(IsOptedInForAccountStorage(&pref_service, &sync_service));
+  EXPECT_TRUE(ShouldShowAccountStorageOptIn(&pref_service, &sync_service));
+  EXPECT_EQ(GetDefaultPasswordStore(&pref_service, &sync_service),
+            PasswordForm::Store::kProfileStore);
+}
+
 TEST(PasswordFeatureManagerUtil, AccountStorageKeepSettingsOnlyForUsers) {
   base::test::ScopedFeatureList features;
   features.InitAndEnableFeature(features::kEnablePasswordsAccountStorage);

components/password_manager/core/common/password_manager_features.cc

@@ -156,6 +156,12 @@ const char kMaxMoveToAccountOffersForNonOptedInUser[] =
 
 const int kMaxMoveToAccountOffersForNonOptedInUserDefaultValue = 5;
 
+// If set to true, Chrome will default to saving to the profile store for users
+// who haven't made an explicit choice yet.
+const char kSaveToProfileStoreByDefault[] = "save_to_profile_store_by_default";
+
+const bool kSaveToProfileStoreByDefaultDefaultValue = false;
+
 }  // namespace features
 
 }  // namespace password_manager

components/password_manager/core/common/password_manager_features.h

@@ -57,9 +57,11 @@ extern const char
     kPasswordChangeWithForcedDialogAfterEverySuccessfulSubmission[];
 extern const char kPasswordChangeInSettingsWithForcedWarningForEverySite[];
 
-// |kEnablePasswordAccountStorage| variations.
+// |kEnablePasswordsAccountStorage| variations.
 extern const char kMaxMoveToAccountOffersForNonOptedInUser[];
 extern const int kMaxMoveToAccountOffersForNonOptedInUserDefaultValue;
+extern const char kSaveToProfileStoreByDefault[];
+extern const bool kSaveToProfileStoreByDefaultDefaultValue;
 
 }  // namespace features