[ios] Moves the GAIA refresh logic behind a feature flag.

Disables the feature by default.

BUG=1102794

Change-Id: Ia8132e8d959cc5017f18b5fd31618ae996de8b2e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417654Reviewed-by: Nohemi Fernandez <fernandex@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808869}

components/signin/ios/browser/account_consistency_service.h

@@ -10,6 +10,7 @@
 #include <string>
 
 #include "base/callback.h"
+#include "base/feature_list.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
@@ -32,6 +33,9 @@ class WebStatePolicyDecider;
 class AccountReconcilor;
 class PrefService;
 
+// Feature flag controlling whether to restore GAIA cookies if they are deleted.
+extern const base::Feature kRestoreGAIACookiesIfDeleted;
+
 // Handles actions necessary for keeping the list of Google accounts available
 // on the web and those available on the iOS device from first-party Google apps
 // consistent. This includes setting the Account Consistency cookie,

components/signin/ios/browser/account_consistency_service.mm

@@ -78,6 +78,9 @@ class AccountConsistencyHandler : public web::WebStatePolicyDecider {
 };
 }  // namespace
 
+const base::Feature kRestoreGAIACookiesIfDeleted{
+    "RestoreGAIACookiesIfDeleted", base::FEATURE_DISABLED_BY_DEFAULT};
+
 AccountConsistencyHandler::AccountConsistencyHandler(
     web::WebState* web_state,
     AccountConsistencyService* service,
@@ -245,10 +248,15 @@ void AccountConsistencyService::TriggerGaiaCookieChangeIfDeleted(
       return;
     }
   }
+
   // The SAPISID cookie may have been deleted previous to this update due to
   // ITP restrictions marking Google domains as potential trackers.
-  // Re-generate cookie to ensure that the user is properly signed in.
   LogIOSGaiaCookiesPresentOnNavigation(false);
+
+  if (!base::FeatureList::IsEnabled(kRestoreGAIACookiesIfDeleted)) {
+    return;
+  }
+  // Re-generate cookie to ensure that the user is properly signed in.
   identity_manager_->GetAccountsCookieMutator()->ForceTriggerOnCookieChange();
 }
 

components/signin/ios/browser/account_consistency_service_unittest.mm

@@ -13,6 +13,8 @@
 #include "base/ios/ios_util.h"
 #include "base/test/bind_test_util.h"
 #import "base/test/ios/wait_util.h"
+#include "base/test/metrics/histogram_tester.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/values.h"
 #include "components/content_settings/core/browser/cookie_settings.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
@@ -56,6 +58,10 @@ const char* kYoutubeDomain = "youtube.com";
 // Google domain where the CHROME_CONNECTED cookie is set/removed.
 const char* kCountryGoogleDomain = "google.de";
 
+// Name of the histogram to record whether the GAIA cookie is present.
+const char* kGAIACookiePresentHistogram =
+    "Signin.IOSGaiaCookiePresentOnNavigation";
+
 // Returns a cookie domain that applies for all origins on |host_domain|.
 std::string GetCookieDomain(const std::string& host_domain) {
   DCHECK(net::cookie_util::DomainIsHostOnly(host_domain));
@@ -573,7 +579,7 @@ TEST_F(AccountConsistencyServiceTest, SetChromeConnectedCookieAtUpdateTime) {
 TEST_F(AccountConsistencyServiceTest, SetGaiaCookieUpdateNotUpdateTime) {
   SimulateUpdateGaiaCookie();
 
-  // Advance clock past one-hour Gaia update time.
+  // Advance clock, but stay within the one-hour Gaia update time.
   const base::Time first_update_time = base::Time::Now();
   task_environment_.FastForwardBy(base::TimeDelta::FromMinutes(1));
   SimulateUpdateGaiaCookie();
@@ -592,6 +598,19 @@ TEST_F(AccountConsistencyServiceTest, SetGaiaCookieUpdateAtUpdateTime) {
   EXPECT_EQ(second_update_time, GetGaiaLastUpdateTime());
 }
 
+// Ensures that the presence or absence of GAIA cookies is logged even if the
+// |kRestoreGAIACookiesIfDeleted| experiment is disabled.
+TEST_F(AccountConsistencyServiceTest, GAIACookieStatusLoggedProperly) {
+  base::HistogramTester histogram_tester;
+  base::test::ScopedFeatureList feature_list;
+  feature_list.InitAndDisableFeature(kRestoreGAIACookiesIfDeleted);
+
+  histogram_tester.ExpectTotalCount(kGAIACookiePresentHistogram, 0);
+  SimulateUpdateGaiaCookie();
+  base::RunLoop().RunUntilIdle();
+  histogram_tester.ExpectTotalCount(kGAIACookiePresentHistogram, 1);
+}
+
 // Ensures that set and remove cookie operations are handled in the order
 // they are called resulting in no cookies.
 TEST_F(AccountConsistencyServiceTest, DeleteChromeConnectedCookiesAfterSet) {