Add a flag to enable impl-thread event handling on Mac

content/public/common/content_switches.h

 // 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.
 
 // Defines all the "content" command-line switches.
 
 #ifndef CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 
 #include "build/build_config.h"
@@ skipping 258 matching lines @@
 CONTENT_EXPORT extern const char kDisablePanelFitting[];
 CONTENT_EXPORT extern const char kDisableVaapiAcceleratedVideoEncode[];
 #endif
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 CONTENT_EXPORT extern const char kEnableSpeechDispatcher[];
 #endif
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 extern const char kDisableCoreAnimationPlugins[];
+extern const char kEnableThreadedEventHandlingMac[];
 #endif
 
 #if defined(OS_WIN)
 // This switch contains the device scale factor passed to certain processes
 // like renderers, etc.
 CONTENT_EXPORT extern const char kDeviceScaleFactor[];
 CONTENT_EXPORT extern const char kDisableLegacyIntermediateWindow[];
 // This switch will be removed when we enable the win32K lockdown process
 // mitigation.
 CONTENT_EXPORT extern const char kEnableWin32kRendererLockDown[];
 #endif
 
 #if defined(ENABLE_PLUGINS)
 CONTENT_EXPORT extern const char kEnablePluginPowerSaver[];
 #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  // CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_