[iOS] Don't sign out the user when FirstSetupComplete flag is off

Don't sign out the user when FirstSetupComplete flag is off when
UnifiedConsent is on.

Bug: 948681
Change-Id: I8da53595d1e89652e9e566d5402a2733aec21f30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1554672
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649660}

ios/chrome/browser/signin/BUILD.gn

@@ -70,6 +70,7 @@ source_set("signin") {
     "//components/signin/ios/browser",
     "//components/signin/ios/browser:active_state_manager",
     "//components/sync",
+    "//components/unified_consent",
     "//google_apis",
     "//ios/chrome/browser",
     "//ios/chrome/browser/bookmarks:bookmarks_utils",

ios/chrome/browser/signin/authentication_service.mm

@@ -18,6 +18,7 @@
 #include "components/signin/core/browser/account_info.h"
 #include "components/sync/driver/sync_service.h"
 #include "components/sync/driver/sync_user_settings.h"
+#include "components/unified_consent/feature.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 #include "ios/chrome/browser/crash_report/breakpad_helper.h"
 #include "ios/chrome/browser/pref_names.h"
@@ -112,15 +113,14 @@ void AuthenticationService::Initialize(
   HandleForgottenIdentity(nil, true /* should_prompt */);
 
   bool is_signed_in = IsAuthenticated();
-  if (is_signed_in) {
-    if (!sync_setup_service_->HasFinishedInitialSetup()) {
+  if (is_signed_in && !unified_consent::IsUnifiedConsentFeatureEnabled() &&
+      !sync_setup_service_->HasFinishedInitialSetup()) {
     // Sign out the user if sync was not configured after signing
     // in (see PM comments in http://crbug.com/339831 ).
     SignOut(signin_metrics::ABORT_SIGNIN, nil);
     SetPromptForSignIn(true);
     is_signed_in = false;
   }
-  }
   breakpad_helper::SetCurrentlySignedIn(is_signed_in);
 
   OnApplicationEnterForeground();