make new syncer thread the default.

chrome/common/chrome_switches.h

 // Copyright (c) 2011 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.
 
 // Defines all the command-line switches used by Chrome.
 
 #ifndef CHROME_COMMON_CHROME_SWITCHES_H_
 #define CHROME_COMMON_CHROME_SWITCHES_H_
 #pragma once
 
@@ skipping 262 matching lines @@
 extern const char kSilentDumpOnDCHECK[];
 extern const char kSimpleDataSource[];
 extern const char kStartMaximized[];
 extern const char kSyncAllowInsecureXmppConnection[];
 extern const char kSyncInvalidateXmppLogin[];
 extern const char kSyncerThreadTimedStop[];
 extern const char kSyncNotificationMethod[];
 extern const char kSyncNotificationHost[];
 extern const char kSyncServiceURL[];
 extern const char kSyncTrySsltcpFirstForXmpp[];
-extern const char kNewSyncerThread[];
 extern const char kTestNaClSandbox[];
 extern const char kTestName[];
 extern const char kTestType[];
 extern const char kTestingChannelID[];
 extern const char kTrustedPlugins[];
 extern const char kTryChromeAgain[];
 extern const char kUninstall[];
 extern const char kUseSpdy[];
 extern const char kIgnoreCertificateErrors[];
 extern const char kMaxSpdySessionsPerDomain[];
@@ skipping 80 matching lines @@
 #if defined(HAVE_XINPUT2)
 extern const char kTouchDevices[];
 #endif
 
 // DON'T ADD RANDOM STUFF HERE. Put it in the main section above in
 // alphabetical order, or in one of the ifdefs (also in order in each section).
 
 }  // namespace switches
 
 #endif  // CHROME_COMMON_CHROME_SWITCHES_H_