arc-bridge: Enable ARC with a command-line flag

chromeos/chromeos_switches.cc

Index: chromeos/chromeos_switches.cc
diff --git a/chromeos/chromeos_switches.cc b/chromeos/chromeos_switches.cc
index 2c1ce3dc7bd9a0deb5f2ad4efc52450fdf644d4b..2586f73af9f00187c43440e739f54b3ec2a97269 100644
--- a/chromeos/chromeos_switches.cc
+++ b/chromeos/chromeos_switches.cc
@@ -104,6 +104,9 @@ const char kDisableNetworkPortalNotification[] =
 const char kEafeUrl[] = "eafe-url";
 const char kEafePath[] = "eafe-path";
 
+// Enables starting the ARC instance upon session start.
+const char kEnableArc[] = "enable-arc";
+
 // Enables consumer management, which allows user to enroll, remotely lock and
 // locate the device.
 const char kEnableConsumerManagement[] = "enable-consumer-management";