Remove the temporary flag to disable the sync confirmation page on linux an windows.

chrome/browser/ui/sync/one_click_signin_sync_starter.cc

 // Copyright (c) 2012 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/ui/sync/one_click_signin_sync_starter.h"
 
 #include <stddef.h>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 304 matching lines @@
       DCHECK(!old_signin_manager->GetUsernameForAuthInProgress().empty());
       DCHECK(!old_signin_manager->IsAuthenticated());
       DCHECK(!new_signin_manager->IsAuthenticated());
 
       // Copy credentials from the old profile to the just-created profile,
       // and switch over to tracking that profile.
       new_signin_manager->CopyCredentialsFrom(*old_signin_manager);
       FinishProfileSyncServiceSetup();
       Initialize(new_profile, nullptr);
       DCHECK_EQ(profile_, new_profile);
+
+#if defined(OS_MACOSX)
+      // On macOS, the sync confirmation dialog is web-contents modal and thus
+      // it is dismissed on tab navigation (which always occurs when signing in
+      // to a new profile).
+      // Skip sync confirmation on macOS to workaround this issue.
       skip_sync_confirm_ = true;
+#endif
 
       // We've transferred our credentials to the new profile - notify that
       // the signin for the original profile was cancelled (must do this after
       // we have called Initialize() with the new profile, as otherwise this
       // object will get freed when the signin on the old profile is cancelled.
       old_signin_manager->SignOut(signin_metrics::TRANSFER_CREDENTIALS,
                                   signin_metrics::SignoutDelete::IGNORE_METRIC);
 
       if (!dm_token_.empty()) {
         // Load policy for the just-created profile - once policy has finished
@@ skipping 151 matching lines @@
 void OneClickSigninSyncStarter::AccountAddedToCookie(
     const GoogleServiceAuthError& error) {
   if (first_account_added_to_cookie_)
     return;
 
   first_account_added_to_cookie_ = true;
 
   // Regardless of whether the account was successfully added or not,
   // continue with sync starting.
 
-  // TODO(zmin): Remove this hack once the https://crbug.com/657924 fixed.
-  // Skip the Sync confirmation dialog if user choose to create a new profile
-  // for the corp signin. This is because the dialog doesn't work properly
-  // after the corp signin.
   if (skip_sync_confirm_) {
     OnSyncConfirmationUIClosed(LoginUIService::ABORT_SIGNIN);
     return;
   }
 
   if (switches::UsePasswordSeparatedSigninFlow()) {
     // Under the new signin flow, the sync confirmation dialog should always be
     // shown regardless of |start_mode_|. |sync_setup_completed_callback_| will
     // be run after the modal is closed.
     DisplayModalSyncConfirmationWindow();
@@ skipping 168 matching lines @@
                                             false /* user_gesture */);
 }
 
 void OneClickSigninSyncStarter::LoadContinueUrl() {
   web_contents()->GetController().LoadURL(
       continue_url_,
       content::Referrer(),
       ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
       std::string());
 }