diff --git a/chrome/browser/signin/chrome_signin_client.cc b/chrome/browser/signin/chrome_signin_client.cc
index 376f4814fbe8f0..37a32295b38cc5 100644
--- a/chrome/browser/signin/chrome_signin_client.cc
+++ b/chrome/browser/signin/chrome_signin_client.cc
@@ -301,10 +301,9 @@ void ChromeSigninClient::DelayNetworkCall(base::OnceClosure callback) {
 
 std::unique_ptr<GaiaAuthFetcher> ChromeSigninClient::CreateGaiaAuthFetcher(
     GaiaAuthConsumer* consumer,
-    gaia::GaiaSource source,
-    scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) {
+    gaia::GaiaSource source) {
   return std::make_unique<GaiaAuthFetcher>(consumer, source,
-                                           url_loader_factory);
+                                           GetURLLoaderFactory());
 }
 
 void ChromeSigninClient::VerifySyncToken() {
diff --git a/chrome/browser/signin/chrome_signin_client.h b/chrome/browser/signin/chrome_signin_client.h
index f225d5403b65de..93d4eded04dba3 100644
--- a/chrome/browser/signin/chrome_signin_client.h
+++ b/chrome/browser/signin/chrome_signin_client.h
@@ -62,9 +62,7 @@ class ChromeSigninClient
   void DelayNetworkCall(base::OnceClosure callback) override;
   std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
-      override;
+      gaia::GaiaSource source) override;
 
   // Returns a string describing the chrome version environment. Version format:
   // <Build Info> <OS> <Version number> (<Last change>)<channel or "-devel">
diff --git a/chrome/browser/signin/dice_response_handler.cc b/chrome/browser/signin/dice_response_handler.cc
index ea2ebd4babc43c..e1275238e5635c 100644
--- a/chrome/browser/signin/dice_response_handler.cc
+++ b/chrome/browser/signin/dice_response_handler.cc
@@ -176,8 +176,8 @@ DiceResponseHandler::DiceTokenFetcher::DiceTokenFetcher(
   DCHECK(dice_response_handler_);
   account_reconcilor_lock_ =
       std::make_unique<AccountReconcilor::Lock>(account_reconcilor);
-  gaia_auth_fetcher_ = signin_client->CreateGaiaAuthFetcher(
-      this, gaia::GaiaSource::kChrome, signin_client->GetURLLoaderFactory());
+  gaia_auth_fetcher_ =
+      signin_client->CreateGaiaAuthFetcher(this, gaia::GaiaSource::kChrome);
   VLOG(1) << "Start fetching token for account: " << email;
   gaia_auth_fetcher_->StartAuthCodeForOAuth2TokenExchange(authorization_code_);
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
diff --git a/chrome/browser/signin/dice_response_handler_unittest.cc b/chrome/browser/signin/dice_response_handler_unittest.cc
index 9c035942f72c52..47876e32a230cf 100644
--- a/chrome/browser/signin/dice_response_handler_unittest.cc
+++ b/chrome/browser/signin/dice_response_handler_unittest.cc
@@ -52,17 +52,14 @@ class DiceTestSigninClient : public TestSigninClient, public GaiaAuthConsumer {
 
   std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
-      override {
+      gaia::GaiaSource source) override {
     DCHECK(!consumer_ || (consumer_ == consumer));
     consumer_ = consumer;
 
     // Pass |this| as a dummy consumer to CreateGaiaAuthFetcher().
     // Since DiceTestSigninClient does not overrides any consumer method,
     // everything will be dropped on the floor.
-    return TestSigninClient::CreateGaiaAuthFetcher(this, source,
-                                                   url_loader_factory);
+    return TestSigninClient::CreateGaiaAuthFetcher(this, source);
   }
 
   GaiaAuthConsumer* consumer_;
diff --git a/components/signin/core/browser/account_reconcilor_unittest.cc b/components/signin/core/browser/account_reconcilor_unittest.cc
index fd6c3f3a0f390a..a1d22a5f74ed73 100644
--- a/components/signin/core/browser/account_reconcilor_unittest.cc
+++ b/components/signin/core/browser/account_reconcilor_unittest.cc
@@ -328,8 +328,8 @@ INSTANTIATE_TEST_SUITE_P(Dice_Mirror,
 
 AccountReconcilorTest::AccountReconcilorTest()
     : account_consistency_(signin::AccountConsistencyMethod::kDisabled),
-      test_signin_client_(&pref_service_),
-      identity_test_env_(&test_url_loader_factory_,
+      test_signin_client_(&pref_service_, &test_url_loader_factory_),
+      identity_test_env_(/*test_url_loader_factory=*/nullptr,
                          &pref_service_,
                          account_consistency_,
                          &test_signin_client_) {
diff --git a/components/signin/core/browser/gaia_cookie_manager_service.cc b/components/signin/core/browser/gaia_cookie_manager_service.cc
index 46bf3592eccd77..50df29db16b6ec 100644
--- a/components/signin/core/browser/gaia_cookie_manager_service.cc
+++ b/components/signin/core/browser/gaia_cookie_manager_service.cc
@@ -259,7 +259,7 @@ void GaiaCookieManagerService::ExternalCcResultFetcher::Start() {
   CleanupTransientState();
   results_.clear();
   helper_->gaia_auth_fetcher_ = helper_->signin_client_->CreateGaiaAuthFetcher(
-      this, gaia::GaiaSource::kChrome, helper_->GetURLLoaderFactory());
+      this, gaia::GaiaSource::kChrome);
   helper_->gaia_auth_fetcher_->StartGetCheckConnectionInfo();
 
   // Some fetches may timeout.  Start a timer to decide when the result fetcher
@@ -451,20 +451,8 @@ void GaiaCookieManagerService::ExternalCcResultFetcher::
 GaiaCookieManagerService::GaiaCookieManagerService(
     OAuth2TokenService* token_service,
     SigninClient* signin_client)
-    : GaiaCookieManagerService(
-          token_service,
-          signin_client,
-          base::BindRepeating(&SigninClient::GetURLLoaderFactory,
-                              base::Unretained(signin_client))) {}
-
-GaiaCookieManagerService::GaiaCookieManagerService(
-    OAuth2TokenService* token_service,
-    SigninClient* signin_client,
-    base::RepeatingCallback<scoped_refptr<network::SharedURLLoaderFactory>()>
-        shared_url_loader_factory_getter)
     : token_service_(token_service),
       signin_client_(signin_client),
-      shared_url_loader_factory_getter_(shared_url_loader_factory_getter),
       external_cc_result_fetcher_(this),
       fetcher_backoff_(&kBackoffPolicy),
       fetcher_retries_(0),
@@ -684,7 +672,7 @@ void GaiaCookieManagerService::CancelAll() {
 
 scoped_refptr<network::SharedURLLoaderFactory>
 GaiaCookieManagerService::GetURLLoaderFactory() {
-  return shared_url_loader_factory_getter_.Run();
+  return signin_client_->GetURLLoaderFactory();
 }
 
 void GaiaCookieManagerService::MarkListAccountsStale() {
@@ -939,18 +927,17 @@ void GaiaCookieManagerService::StartFetchingUbertoken() {
                      base::Unretained(this)),
       base::BindRepeating(
           [](SigninClient* client,
-             scoped_refptr<network::SharedURLLoaderFactory> url_loader,
              GaiaAuthConsumer* consumer) -> std::unique_ptr<GaiaAuthFetcher> {
-            return client->CreateGaiaAuthFetcher(
-                consumer, gaia::GaiaSource::kChrome, url_loader);
+            return client->CreateGaiaAuthFetcher(consumer,
+                                                 gaia::GaiaSource::kChrome);
           },
-          base::Unretained(signin_client_), GetURLLoaderFactory()));
+          base::Unretained(signin_client_)));
 }
 
 void GaiaCookieManagerService::StartFetchingMergeSession() {
   DCHECK(!uber_token_.empty());
-  gaia_auth_fetcher_ = signin_client_->CreateGaiaAuthFetcher(
-      this, requests_.front().source(), GetURLLoaderFactory());
+  gaia_auth_fetcher_ =
+      signin_client_->CreateGaiaAuthFetcher(this, requests_.front().source());
 
   gaia_auth_fetcher_->StartMergeSession(
       uber_token_, external_cc_result_fetcher_.GetExternalCcResult());
@@ -967,15 +954,15 @@ void GaiaCookieManagerService::StartGaiaLogOut() {
 
 void GaiaCookieManagerService::StartFetchingLogOut() {
   RecordLogoutRequestState(LogoutRequestState::kStarted);
-  gaia_auth_fetcher_ = signin_client_->CreateGaiaAuthFetcher(
-      this, requests_.front().source(), GetURLLoaderFactory());
+  gaia_auth_fetcher_ =
+      signin_client_->CreateGaiaAuthFetcher(this, requests_.front().source());
   gaia_auth_fetcher_->StartLogOut();
 }
 
 void GaiaCookieManagerService::StartFetchingListAccounts() {
   VLOG(1) << "GaiaCookieManagerService::ListAccounts";
-  gaia_auth_fetcher_ = signin_client_->CreateGaiaAuthFetcher(
-      this, requests_.front().source(), GetURLLoaderFactory());
+  gaia_auth_fetcher_ =
+      signin_client_->CreateGaiaAuthFetcher(this, requests_.front().source());
   gaia_auth_fetcher_->StartListAccounts();
 }
 
diff --git a/components/signin/core/browser/gaia_cookie_manager_service.h b/components/signin/core/browser/gaia_cookie_manager_service.h
index 6c361383afb812..13aeee10cb0835 100644
--- a/components/signin/core/browser/gaia_cookie_manager_service.h
+++ b/components/signin/core/browser/gaia_cookie_manager_service.h
@@ -228,19 +228,6 @@ class GaiaCookieManagerService : public GaiaAuthConsumer,
   GaiaCookieManagerService(OAuth2TokenService* token_service,
                            SigninClient* signin_client);
 
-  // Creates a GaiaCookieManagerService that uses the provided
-  // |shared_url_loader_factory_getter| to determine the SharedUrlLoaderFactory
-  // used for cookie-related requests.
-  // Note: SharedUrlLoaderFactory is passed via callback, so that if the
-  // callback has side-effects (e.g. network initialization), they do not occur
-  // until the first time GaiaCookieManagerService::GetSharedUrlLoaderFactory is
-  // called.
-  GaiaCookieManagerService(
-      OAuth2TokenService* token_service,
-      SigninClient* signin_client,
-      base::RepeatingCallback<scoped_refptr<network::SharedURLLoaderFactory>()>
-          shared_url_loader_factory_getter);
-
   ~GaiaCookieManagerService() override;
 
   void InitCookieListener();
@@ -373,8 +360,6 @@ class GaiaCookieManagerService : public GaiaAuthConsumer,
   OAuth2TokenService* token_service_;
   SigninClient* signin_client_;
 
-  base::RepeatingCallback<scoped_refptr<network::SharedURLLoaderFactory>()>
-      shared_url_loader_factory_getter_;
   std::unique_ptr<GaiaAuthFetcher> gaia_auth_fetcher_;
   std::unique_ptr<signin::UbertokenFetcherImpl> uber_token_fetcher_;
   ExternalCcResultFetcher external_cc_result_fetcher_;
diff --git a/components/signin/core/browser/gaia_cookie_manager_service_unittest.cc b/components/signin/core/browser/gaia_cookie_manager_service_unittest.cc
index 727be0c555a195..7ce329e826dbea 100644
--- a/components/signin/core/browser/gaia_cookie_manager_service_unittest.cc
+++ b/components/signin/core/browser/gaia_cookie_manager_service_unittest.cc
@@ -96,11 +96,7 @@ class InstrumentedGaiaCookieManagerService : public GaiaCookieManagerService {
  public:
   InstrumentedGaiaCookieManagerService(OAuth2TokenService* token_service,
                                        SigninClient* signin_client)
-      : GaiaCookieManagerService(
-            token_service,
-            signin_client,
-            base::BindRepeating(&SigninClient::GetURLLoaderFactory,
-                                base::Unretained(signin_client))) {
+      : GaiaCookieManagerService(token_service, signin_client) {
     total++;
   }
 
diff --git a/components/signin/core/browser/oauth_multilogin_helper.cc b/components/signin/core/browser/oauth_multilogin_helper.cc
index 0d43d8a6d37ce2..230678cbd6d03c 100644
--- a/components/signin/core/browser/oauth_multilogin_helper.cc
+++ b/components/signin/core/browser/oauth_multilogin_helper.cc
@@ -100,8 +100,8 @@ void OAuthMultiloginHelper::OnAccessTokensFailure(
 
 void OAuthMultiloginHelper::StartFetchingMultiLogin() {
   DCHECK_EQ(token_id_pairs_.size(), account_ids_.size());
-  gaia_auth_fetcher_ = signin_client_->CreateGaiaAuthFetcher(
-      this, gaia::GaiaSource::kChrome, signin_client_->GetURLLoaderFactory());
+  gaia_auth_fetcher_ =
+      signin_client_->CreateGaiaAuthFetcher(this, gaia::GaiaSource::kChrome);
   gaia_auth_fetcher_->StartOAuthMultilogin(token_id_pairs_);
 }
 
diff --git a/components/signin/core/browser/signin_client.h b/components/signin/core/browser/signin_client.h
index e49465d46d148b..8587e23de6cef2 100644
--- a/components/signin/core/browser/signin_client.h
+++ b/components/signin/core/browser/signin_client.h
@@ -95,8 +95,7 @@ class SigninClient : public KeyedService {
   // Creates a new platform-specific GaiaAuthFetcher.
   virtual std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) = 0;
+      gaia::GaiaSource source) = 0;
 
   // Schedules migration to happen at next startup.
   virtual void SetReadyForDiceMigration(bool is_ready) {}
diff --git a/components/signin/core/browser/test_signin_client.cc b/components/signin/core/browser/test_signin_client.cc
index 3f945fea727598..a870fe44eb941f 100644
--- a/components/signin/core/browser/test_signin_client.cc
+++ b/components/signin/core/browser/test_signin_client.cc
@@ -12,8 +12,11 @@
 #include "services/network/test/test_cookie_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-TestSigninClient::TestSigninClient(PrefService* pref_service)
-    : pref_service_(pref_service),
+TestSigninClient::TestSigninClient(
+    PrefService* pref_service,
+    network::TestURLLoaderFactory* test_url_loader_factory)
+    : test_url_loader_factory_(test_url_loader_factory),
+      pref_service_(pref_service),
       are_signin_cookies_allowed_(true),
       network_calls_delayed_(false),
       is_signout_allowed_(true),
@@ -37,7 +40,7 @@ void TestSigninClient::PreSignOut(
 
 scoped_refptr<network::SharedURLLoaderFactory>
 TestSigninClient::GetURLLoaderFactory() {
-  return test_url_loader_factory_.GetSafeWeakWrapper();
+  return test_url_loader_factory()->GetSafeWeakWrapper();
 }
 
 network::mojom::CookieManager* TestSigninClient::GetCookieManager() {
@@ -46,6 +49,25 @@ network::mojom::CookieManager* TestSigninClient::GetCookieManager() {
   return cookie_manager_.get();
 }
 
+network::TestURLLoaderFactory* TestSigninClient::test_url_loader_factory() {
+  if (test_url_loader_factory_)
+    return test_url_loader_factory_;
+
+  if (!default_test_url_loader_factory_) {
+    default_test_url_loader_factory_ =
+        std::make_unique<network::TestURLLoaderFactory>();
+  }
+
+  return default_test_url_loader_factory_.get();
+}
+
+void TestSigninClient::OverrideTestUrlLoaderFactory(
+    network::TestURLLoaderFactory* factory) {
+  DCHECK(!default_test_url_loader_factory_);
+  DCHECK(!test_url_loader_factory_);
+  test_url_loader_factory_ = factory;
+}
+
 std::string TestSigninClient::GetProductVersion() { return ""; }
 
 void TestSigninClient::SetNetworkCallsDelayed(bool value) {
@@ -92,10 +114,9 @@ void TestSigninClient::DelayNetworkCall(base::OnceClosure callback) {
 
 std::unique_ptr<GaiaAuthFetcher> TestSigninClient::CreateGaiaAuthFetcher(
     GaiaAuthConsumer* consumer,
-    gaia::GaiaSource source,
-    scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) {
+    gaia::GaiaSource source) {
   return std::make_unique<GaiaAuthFetcher>(consumer, source,
-                                           url_loader_factory);
+                                           GetURLLoaderFactory());
 }
 
 void TestSigninClient::PreGaiaLogout(base::OnceClosure callback) {
diff --git a/components/signin/core/browser/test_signin_client.h b/components/signin/core/browser/test_signin_client.h
index ac713d6bdf296c..5fafc514605523 100644
--- a/components/signin/core/browser/test_signin_client.h
+++ b/components/signin/core/browser/test_signin_client.h
@@ -27,7 +27,9 @@ class PrefService;
 // part of its interface.
 class TestSigninClient : public SigninClient {
  public:
-  TestSigninClient(PrefService* pref_service);
+  TestSigninClient(
+      PrefService* pref_service,
+      network::TestURLLoaderFactory* test_url_loader_factory = nullptr);
   ~TestSigninClient() override;
 
   // SigninClient implementation that is specialized for unit tests.
@@ -57,9 +59,12 @@ class TestSigninClient : public SigninClient {
     cookie_manager_ = std::move(cookie_manager);
   }
 
-  network::TestURLLoaderFactory* test_url_loader_factory() {
-    return &test_url_loader_factory_;
-  }
+  // Returns |test_url_loader_factory_| if it is specified. Otherwise, lazily
+  // creates a default factory and returns it.
+  network::TestURLLoaderFactory* test_url_loader_factory();
+
+  // Pass a TestURLLoader factory to use instead of the default one.
+  void OverrideTestUrlLoaderFactory(network::TestURLLoaderFactory* factory);
 
   void set_are_signin_cookies_allowed(bool value) {
     are_signin_cookies_allowed_ = value;
@@ -87,14 +92,14 @@ class TestSigninClient : public SigninClient {
   void DelayNetworkCall(base::OnceClosure callback) override;
   std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
-      override;
+      gaia::GaiaSource source) override;
   void PreGaiaLogout(base::OnceClosure callback) override;
   void SetReadyForDiceMigration(bool ready) override;
 
  private:
-  network::TestURLLoaderFactory test_url_loader_factory_;
+  std::unique_ptr<network::TestURLLoaderFactory>
+      default_test_url_loader_factory_;
+  network::TestURLLoaderFactory* test_url_loader_factory_;
 
   PrefService* pref_service_;
   std::unique_ptr<network::mojom::CookieManager> cookie_manager_;
diff --git a/components/signin/ios/browser/account_consistency_service_unittest.mm b/components/signin/ios/browser/account_consistency_service_unittest.mm
index 6afb87dda2afc2..0a2e3d0648f758 100644
--- a/components/signin/ios/browser/account_consistency_service_unittest.mm
+++ b/components/signin/ios/browser/account_consistency_service_unittest.mm
@@ -130,9 +130,10 @@ void SetUp() override {
     HostContentSettingsMap::RegisterProfilePrefs(prefs_.registry());
 
     web_view_load_expection_count_ = 0;
-    signin_client_.reset(new TestSigninClient(&prefs_));
+    signin_client_.reset(
+        new TestSigninClient(&prefs_, &test_url_loader_factory_));
     identity_test_env_.reset(new identity::IdentityTestEnvironment(
-        &test_url_loader_factory_, &prefs_,
+        /*test_url_loader_factory=*/nullptr, &prefs_,
         signin::AccountConsistencyMethod::kDisabled, signin_client_.get()));
     settings_map_ = new HostContentSettingsMap(
         &prefs_, false /* is_off_the_record */, false /* store_last_modified */,
diff --git a/ios/chrome/browser/signin/identity_test_environment_chrome_browser_state_adaptor.cc b/ios/chrome/browser/signin/identity_test_environment_chrome_browser_state_adaptor.cc
index e693366b0961d6..f782dceb5eb7d1 100644
--- a/ios/chrome/browser/signin/identity_test_environment_chrome_browser_state_adaptor.cc
+++ b/ios/chrome/browser/signin/identity_test_environment_chrome_browser_state_adaptor.cc
@@ -110,8 +110,7 @@ std::unique_ptr<KeyedService> IdentityTestEnvironmentChromeBrowserStateAdaptor::
   return identity::IdentityTestEnvironment::BuildIdentityManagerForTests(
       SigninClientFactory::GetForBrowserState(chrome_browser_state),
       chrome_browser_state->GetPrefs(), base::FilePath(),
-      signin::AccountConsistencyMethod::kMirror,
-      /*test_url_loader_factory=*/nullptr, std::move(extra_params));
+      signin::AccountConsistencyMethod::kMirror, std::move(extra_params));
 }
 
 // static
diff --git a/ios/chrome/browser/signin/ios_chrome_signin_client.h b/ios/chrome/browser/signin/ios_chrome_signin_client.h
index ddb9fd0e5cc766..cdcb9f7fc1dc4c 100644
--- a/ios/chrome/browser/signin/ios_chrome_signin_client.h
+++ b/ios/chrome/browser/signin/ios_chrome_signin_client.h
@@ -35,9 +35,7 @@ class IOSChromeSigninClient : public SigninClient {
   std::string GetProductVersion() override;
   std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
-      override;
+      gaia::GaiaSource source) override;
   void PreGaiaLogout(base::OnceClosure callback) override;
   PrefService* GetPrefs() override;
   scoped_refptr<network::SharedURLLoaderFactory> GetURLLoaderFactory() override;
diff --git a/ios/chrome/browser/signin/ios_chrome_signin_client.mm b/ios/chrome/browser/signin/ios_chrome_signin_client.mm
index f9900765004413..1fa899fe91bdc2 100644
--- a/ios/chrome/browser/signin/ios_chrome_signin_client.mm
+++ b/ios/chrome/browser/signin/ios_chrome_signin_client.mm
@@ -95,10 +95,9 @@
 
 std::unique_ptr<GaiaAuthFetcher> IOSChromeSigninClient::CreateGaiaAuthFetcher(
     GaiaAuthConsumer* consumer,
-    gaia::GaiaSource source,
-    scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) {
+    gaia::GaiaSource source) {
   return std::make_unique<GaiaAuthFetcherIOS>(
-      consumer, source, url_loader_factory, browser_state_);
+      consumer, source, GetURLLoaderFactory(), browser_state_);
 }
 
 void IOSChromeSigninClient::PreGaiaLogout(base::OnceClosure callback) {
diff --git a/ios/web_view/internal/signin/ios_web_view_signin_client.h b/ios/web_view/internal/signin/ios_web_view_signin_client.h
index 3e95a9ddfdbd89..e447fb480fe93b 100644
--- a/ios/web_view/internal/signin/ios_web_view_signin_client.h
+++ b/ios/web_view/internal/signin/ios_web_view_signin_client.h
@@ -52,9 +52,7 @@ class IOSWebViewSigninClient : public SigninClient {
   void DelayNetworkCall(base::OnceClosure callback) override;
   std::unique_ptr<GaiaAuthFetcher> CreateGaiaAuthFetcher(
       GaiaAuthConsumer* consumer,
-      gaia::GaiaSource source,
-      scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
-      override;
+      gaia::GaiaSource source) override;
 
   // CWVSyncController setter/getter.
   void SetSyncController(CWVSyncController* sync_controller);
diff --git a/ios/web_view/internal/signin/ios_web_view_signin_client.mm b/ios/web_view/internal/signin/ios_web_view_signin_client.mm
index 2e22b4f4170521..eb237084f99a44 100644
--- a/ios/web_view/internal/signin/ios_web_view_signin_client.mm
+++ b/ios/web_view/internal/signin/ios_web_view_signin_client.mm
@@ -95,10 +95,9 @@
 
 std::unique_ptr<GaiaAuthFetcher> IOSWebViewSigninClient::CreateGaiaAuthFetcher(
     GaiaAuthConsumer* consumer,
-    gaia::GaiaSource source,
-    scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) {
+    gaia::GaiaSource source) {
   return std::make_unique<GaiaAuthFetcher>(consumer, source,
-                                           url_loader_factory);
+                                           GetURLLoaderFactory());
 }
 
 void IOSWebViewSigninClient::SetSyncController(
diff --git a/services/identity/public/cpp/accounts_cookie_mutator_unittest.cc b/services/identity/public/cpp/accounts_cookie_mutator_unittest.cc
index 68af7ac4f1995c..d4033f6827f01f 100644
--- a/services/identity/public/cpp/accounts_cookie_mutator_unittest.cc
+++ b/services/identity/public/cpp/accounts_cookie_mutator_unittest.cc
@@ -63,7 +63,7 @@ class AccountsCookieMutatorTest : public testing::Test {
  public:
   AccountsCookieMutatorTest()
       : test_signin_client_(&prefs_),
-        identity_test_env_(test_url_loader_factory(),
+        identity_test_env_(/*test_url_loader_factory=*/nullptr,
                            &prefs_,
                            signin::AccountConsistencyMethod::kDisabled,
                            &test_signin_client_) {}
diff --git a/services/identity/public/cpp/identity_manager_unittest.cc b/services/identity/public/cpp/identity_manager_unittest.cc
index d1736fbb48c648..bd196ec739fe4b 100644
--- a/services/identity/public/cpp/identity_manager_unittest.cc
+++ b/services/identity/public/cpp/identity_manager_unittest.cc
@@ -212,7 +212,8 @@ class TestIdentityManagerDiagnosticsObserver
 
 class IdentityManagerTest : public testing::Test {
  protected:
-  IdentityManagerTest() : signin_client_(&pref_service_) {
+  IdentityManagerTest()
+      : signin_client_(&pref_service_, &test_url_loader_factory_) {
     IdentityManager::RegisterProfilePrefs(pref_service_.registry());
     IdentityManager::RegisterLocalStatePrefs(pref_service_.registry());
 
@@ -280,14 +281,8 @@ class IdentityManagerTest : public testing::Test {
         std::make_unique<CustomFakeProfileOAuth2TokenService>(&pref_service_);
 
     auto gaia_cookie_manager_service =
-        std::make_unique<GaiaCookieManagerService>(
-            token_service.get(), &signin_client_,
-            base::BindRepeating(
-                [](network::TestURLLoaderFactory* test_url_loader_factory)
-                    -> scoped_refptr<network::SharedURLLoaderFactory> {
-                  return test_url_loader_factory->GetSafeWeakWrapper();
-                },
-                test_url_loader_factory()));
+        std::make_unique<GaiaCookieManagerService>(token_service.get(),
+                                                   &signin_client_);
 
     auto account_tracker_service = std::make_unique<AccountTrackerService>();
     account_tracker_service->Initialize(&pref_service_, base::FilePath());
@@ -375,8 +370,8 @@ class IdentityManagerTest : public testing::Test {
  private:
   base::MessageLoop message_loop_;
   sync_preferences::TestingPrefServiceSyncable pref_service_;
-  TestSigninClient signin_client_;
   network::TestURLLoaderFactory test_url_loader_factory_;
+  TestSigninClient signin_client_;
   std::unique_ptr<IdentityManager> identity_manager_;
   std::unique_ptr<TestIdentityManagerObserver> identity_manager_observer_;
   std::unique_ptr<TestIdentityManagerDiagnosticsObserver>
diff --git a/services/identity/public/cpp/identity_test_environment.cc b/services/identity/public/cpp/identity_test_environment.cc
index 3c47a494fd85b9..177e7e0ec29623 100644
--- a/services/identity/public/cpp/identity_test_environment.cc
+++ b/services/identity/public/cpp/identity_test_environment.cc
@@ -111,7 +111,9 @@ IdentityTestEnvironment::IdentityTestEnvironment(
               pref_service,
               test_signin_client),
           test_url_loader_factory,
-          account_consistency) {}
+          account_consistency) {
+  DCHECK(!test_url_loader_factory || !test_signin_client);
+}
 
 IdentityTestEnvironment::IdentityTestEnvironment(
     IdentityManager* identity_manager)
@@ -137,19 +139,21 @@ IdentityTestEnvironment::IdentityTestEnvironment(
     std::unique_ptr<IdentityManagerDependenciesOwner> dependencies_owner,
     network::TestURLLoaderFactory* test_url_loader_factory,
     signin::AccountConsistencyMethod account_consistency)
-    : test_url_loader_factory_(test_url_loader_factory),
-      weak_ptr_factory_(this) {
+    : weak_ptr_factory_(this) {
   dependencies_owner_ = std::move(dependencies_owner);
   TestSigninClient* test_signin_client = dependencies_owner_->signin_client();
+  if (test_url_loader_factory)
+    test_signin_client->OverrideTestUrlLoaderFactory(test_url_loader_factory);
+
   sync_preferences::TestingPrefServiceSyncable* test_pref_service =
       dependencies_owner_->pref_service();
 
   IdentityManager::RegisterProfilePrefs(test_pref_service->registry());
   IdentityManager::RegisterLocalStatePrefs(test_pref_service->registry());
 
-  owned_identity_manager_ = BuildIdentityManagerForTests(
-      test_signin_client, test_pref_service, base::FilePath(),
-      account_consistency, test_url_loader_factory);
+  owned_identity_manager_ =
+      BuildIdentityManagerForTests(test_signin_client, test_pref_service,
+                                   base::FilePath(), account_consistency);
 
   Initialize();
 }
@@ -168,7 +172,6 @@ IdentityTestEnvironment::BuildIdentityManagerForTests(
     PrefService* pref_service,
     base::FilePath user_data_dir,
     signin::AccountConsistencyMethod account_consistency,
-    network::TestURLLoaderFactory* test_url_loader_factory,
     ExtraParams extra_params) {
   auto account_tracker_service = std::make_unique<AccountTrackerService>();
   account_tracker_service->Initialize(pref_service, user_data_dir);
@@ -209,19 +212,8 @@ IdentityTestEnvironment::BuildIdentityManagerForTests(
   signin_manager->Initialize(pref_service);
 
   std::unique_ptr<GaiaCookieManagerService> gaia_cookie_manager_service;
-  if (test_url_loader_factory != nullptr) {
-    gaia_cookie_manager_service = std::make_unique<GaiaCookieManagerService>(
-        token_service.get(), signin_client,
-        base::BindRepeating(
-            [](network::TestURLLoaderFactory* test_url_loader_factory)
-                -> scoped_refptr<network::SharedURLLoaderFactory> {
-              return test_url_loader_factory->GetSafeWeakWrapper();
-            },
-            test_url_loader_factory));
-  } else {
     gaia_cookie_manager_service = std::make_unique<GaiaCookieManagerService>(
         token_service.get(), signin_client);
-  }
 
   std::unique_ptr<PrimaryAccountMutator> primary_account_mutator;
   std::unique_ptr<AccountsMutator> accounts_mutator;
@@ -328,11 +320,10 @@ void IdentityTestEnvironment::UpdatePersistentErrorOfRefreshTokenForAccount(
 
 void IdentityTestEnvironment::SetCookieAccounts(
     const std::vector<CookieParams>& cookie_accounts) {
-  DCHECK(test_url_loader_factory_)
-      << "IdentityTestEnvironment constructor must have been passed a "
-         "test_url_loader_factory in order to use this method.";
-  identity::SetCookieAccounts(identity_manager(), test_url_loader_factory_,
-                              cookie_accounts);
+  identity::SetCookieAccounts(
+      identity_manager(),
+      dependencies_owner_->signin_client()->test_url_loader_factory(),
+      cookie_accounts);
 }
 
 void IdentityTestEnvironment::SetAutomaticIssueOfAccessTokens(bool grant) {
diff --git a/services/identity/public/cpp/identity_test_environment.h b/services/identity/public/cpp/identity_test_environment.h
index fbbc1cbdb2f419..2f726f39a10e59 100644
--- a/services/identity/public/cpp/identity_test_environment.h
+++ b/services/identity/public/cpp/identity_test_environment.h
@@ -66,8 +66,14 @@ class IdentityTestEnvironment : public IdentityManager::DiagnosticsObserver {
   // dependencies directly (namely AccountTrackerService, PO2TS), but still be
   // able to tweak preferences on demand.
   //
-  // Last, this constructor can take an optional parameter |account_consistency|
-  // as parameter, to specify the account consistency policy that will be used.
+  // |account_consistency| specifies the account consistency policy that will be
+  // used.
+  //
+  // A specific TestSigninClient instance can be passed optionally. If it is
+  // null, the test environment will automatically build one internally.
+  //
+  // Note: at least one of |test_url_loader_factory| and |test_signin_client|
+  // must be nulltpr. They cannot both be specified at the same time.
   IdentityTestEnvironment(
       network::TestURLLoaderFactory* test_url_loader_factory = nullptr,
       sync_preferences::TestingPrefServiceSyncable* pref_service = nullptr,
@@ -334,10 +340,6 @@ class IdentityTestEnvironment : public IdentityManager::DiagnosticsObserver {
   // Owner of all dependencies that don't belong to IdentityManager.
   std::unique_ptr<IdentityManagerDependenciesOwner> dependencies_owner_;
 
-  // Used to set fake responses for cookie-related requests.
-  // This can be null if no TestURLLoaderFactory was passed via the constructor.
-  network::TestURLLoaderFactory* test_url_loader_factory_ = nullptr;
-
   // This will be null if a TestSigninClient was provided to
   // IdentityTestEnvironment's constructor.
   std::unique_ptr<TestSigninClient> owned_signin_client_;
@@ -377,7 +379,6 @@ class IdentityTestEnvironment : public IdentityManager::DiagnosticsObserver {
       base::FilePath user_data_dir,
       signin::AccountConsistencyMethod account_consistency =
           signin::AccountConsistencyMethod::kDisabled,
-      network::TestURLLoaderFactory* test_url_loader_factory = nullptr,
       ExtraParams extra_params = {});
 
   // Shared constructor initialization logic.