Add autoclick to settings page under the accessibility section.

ash/ash_switches.cc

Index: ash/ash_switches.cc
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 70b1340b289bb486211e3f93c7a771bf72fedb77..394e5a6cea65596c0bad2f033fb097e3acd07cda 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -91,6 +91,9 @@ const char kAshEnableAdvancedGestures[] = "ash-enable-advanced-gestures";
 const char kAshEnableAlternateFrameCaptionButtonStyle[] =
     "ash-enable-alternate-caption-button";
 
+// Enables settings ui to control the autoclick accessibility feature.
+const char kAshEnableAutoclick[] = "ash-enable-autoclick";
+
 // Always enable brightness control. Used by machines that don't report their
 // main monitor as internal.
 const char kAshEnableBrightnessControl[] = "ash-enable-brightness-control";