[Password Manager] Setup experiment to restrict autofilling of sync credential

chrome/browser/password_manager/sync_metrics.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/password_manager/sync_metrics.h"
 
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 #include "google_apis/gaia/gaia_urls.h"
 
 namespace password_manager_sync_metrics {
 
 std::string GetSyncUsername(Profile* profile) {
+  // If sync is set up, return early if we aren't syncing passwords.
+  if (ProfileSyncServiceFactory::HasProfileSyncService(profile)) {
+    ProfileSyncService* sync_service =
+        ProfileSyncServiceFactory::GetForProfile(profile);
+    if (!sync_service->HasSyncSetupCompleted() ||
+        !sync_service->GetActiveDataTypes().Has(syncer::PASSWORDS))
+      return std::string();
+  }
+
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(profile);
+
   if (!signin_manager)
-    return "";
+    return std::string();
 
   return signin_manager->GetAuthenticatedUsername();
 }
 
 bool IsSyncAccountCredential(Profile* profile,
                              const std::string& username,
                              const std::string& origin) {
   if (origin != GaiaUrls::GetInstance()->gaia_url().GetOrigin().spec())
     return false;
 
   return gaia::AreEmailsSame(username, GetSyncUsername(profile));
 }
 
 }  // namespace password_manager_sync_metrics