Use helper DeviceChangeHandler to call mousecontrol/tpcontrol whenever a device is attached.

chrome/browser/chromeos/chrome_browser_main_chromeos.h

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.h
===================================================================
--- chrome/browser/chromeos/chrome_browser_main_chromeos.h	(revision 201865)
+++ chrome/browser/chromeos/chrome_browser_main_chromeos.h	(working copy)
@@ -45,6 +45,7 @@
 
 namespace system {
 class AutomaticRebootManager;
+class DeviceChangeHandler;
 }
 
 class ChromeBrowserMainPartsChromeos : public ChromeBrowserMainPartsLinux {
@@ -89,6 +90,7 @@
   scoped_ptr<StorageMonitorCros> storage_monitor_;
   scoped_ptr<system::AutomaticRebootManager> automatic_reboot_manager_;
   scoped_ptr<IdleActionWarningObserver> idle_action_warning_observer_;
+  scoped_ptr<system::DeviceChangeHandler> device_change_handler_;
 
   scoped_ptr<internal::DBusServices> dbus_services_;