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

content/public/common/content_switches.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 "content/public/common/content_switches.h"
 
 #include "base/command_line.h"
 
 namespace switches {
 
@@ skipping 922 matching lines @@
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 // Allows sending text-to-speech requests to speech-dispatcher, a common
 // Linux speech service. Because it's buggy, the user must explicitly
 // enable it so that visiting a random webpage can't cause instability.
 const char kEnableSpeechDispatcher[] = "enable-speech-dispatcher";
 #endif
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 // Disables support for Core Animation plugins. This is triggered when
-// accelerated compositing is disabled. See http://crbug.com/122430 .
+// accelerated compositing is disabled. See http://crbug.com/122430.
 const char kDisableCoreAnimationPlugins[] =
     "disable-core-animation-plugins";
+
+// Allows input events to be handed on the compositor thread.
+// This feature is under development, see http://crbug.com/138003.
+extern const char kEnableThreadedEventHandlingMac[] =
+    "enable-threaded-event-handling-mac";
 #endif
 
 #if defined(OS_WIN)
 // Device scale factor passed to certain processes like renderers, etc.
 const char kDeviceScaleFactor[]     = "device-scale-factor";
 
 // Disable the Legacy Window which corresponds to the size of the WebContents.
 const char kDisableLegacyIntermediateWindow[] = "disable-legacy-window";
 
 // Enable the Win32K process mitigation policy for renderer processes which
 // prevents them from invoking user32 and gdi32 system calls which enter
 // the kernel. This is only supported on Windows 8 and beyond.
 const char kEnableWin32kRendererLockDown[]
     = "enable_win32k_renderer_lockdown";
 #endif
 
 #if defined(ENABLE_PLUGINS)
 // Enables the plugin power saver feature.
 const char kEnablePluginPowerSaver[] = "enable-plugin-power-saver";
 #endif
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches