Enable tab sync on all platforms by default.

chrome/browser/sync/glue/sync_backend_host.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 "build/build_config.h"
 
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 
 #include <algorithm>
 #include <map>
@@ skipping 1006 matching lines @@
       options.service_url.host() + options.service_url.path(),
       options.service_url.EffectiveIntPort(),
       options.service_url.SchemeIsSecure(),
       BrowserThread::GetBlockingPool(),
       options.make_http_bridge_factory_fn.Run(),
       options.registrar /* as ModelSafeWorkerRegistrar */,
       options.extensions_activity_monitor,
       options.registrar /* as SyncManager::ChangeDelegate */,
       MakeUserAgentForSyncApi(),
       options.credentials,
-      CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableSyncTabsForOtherClients),
+      true,
       new BridgedSyncNotifier(
           options.chrome_sync_notification_bridge,
           options.sync_notifier_factory->CreateSyncNotifier()),
       options.restored_key_for_bootstrapping,
       options.setup_for_test_mode,
       &encryptor_,
       options.unrecoverable_error_handler,
       options.report_unrecoverable_error_function);
   LOG_IF(ERROR, !success) << "Syncapi initialization failed!";
 
@@ skipping 336 matching lines @@
       FROM_HERE,
       base::Bind(&SyncBackendHost::Core::DoRefreshNigori,
                  core_.get(), sync_thread_done_callback));
 }
 
 #undef SDVLOG
 
 #undef SLOG
 
 }  // namespace browser_sync