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

chrome/browser/chromeos/preferences.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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_PREFERENCES_H_
 #define CHROME_BROWSER_CHROMEOS_PREFERENCES_H_
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/prefs/pref_member.h"
 #include "chrome/browser/chromeos/language_preferences.h"
+#include "chrome/browser/chromeos/system/pointer_device_observer.h"
 #include "chrome/browser/prefs/pref_service_syncable_observer.h"
 
 class PrefRegistrySimple;
 class PrefService;
 class PrefServiceSyncable;
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 namespace chromeos {
 
 namespace input_method {
 class InputMethodManager;
 }
 
 // The Preferences class handles Chrome OS preferences. When the class
 // is first initialized, it will initialize the OS settings to what's stored in
 // the preferences. These include touchpad settings, etc.
 // When the preferences change, we change the settings to reflect the new value.
-class Preferences : public PrefServiceSyncableObserver {
+class Preferences : public PrefServiceSyncableObserver,
+                    public system::PointerDeviceObserver::Observer {
  public:
   Preferences();
   explicit Preferences(
       input_method::InputMethodManager* input_method_manager);  // for testing
   virtual ~Preferences();
 
   // These method will register the prefs associated with Chrome OS settings.
   static void RegisterPrefs(PrefRegistrySimple* registry);
   static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
 
@@ skipping 51 matching lines @@
 
   // Updates the initial key repeat delay and key repeat interval following
   // current prefs values. We set the delay and interval at once since an
   // underlying XKB API requires it.
   void UpdateAutoRepeatRate();
 
   // Force natural scroll to on if --enable-natural-scroll-default is specified
   // on the cmd line.
   void ForceNaturalScrollDefault();
 
+  // Helpers for preference changes for mouse and touchpad settings.
+  void SetTouchpadPrefs(const std::string* pref_name);
+  void SetMousePrefs(const std::string* pref_name);
+
   // PrefServiceSyncableObserver implementation.
   virtual void OnIsSyncingChanged() OVERRIDE;
 
+  // PointerDeviceObserver::Observer implementation.
+  virtual void TouchpadExists(bool exists) OVERRIDE;
+  virtual void MouseExists(bool exists) OVERRIDE;
+
   PrefServiceSyncable* prefs_;
 
   input_method::InputMethodManager* input_method_manager_;
+  scoped_ptr<system::PointerDeviceObserver> pointer_device_observer_;
 
   BooleanPrefMember tap_to_click_enabled_;
   BooleanPrefMember tap_dragging_enabled_;
   BooleanPrefMember three_finger_click_enabled_;
   BooleanPrefMember three_finger_swipe_enabled_;
   BooleanPrefMember natural_scroll_;
   BooleanPrefMember vert_edge_scroll_enabled_;
   BooleanPrefMember screen_magnifier_enabled_;
   IntegerPrefMember screen_magnifier_type_;
   DoublePrefMember screen_magnifier_scale_;
@@ skipping 63 matching lines @@
   BooleanPrefMember power_allow_screen_wake_locks_;
   DoublePrefMember power_presentation_idle_delay_factor_;
   DoublePrefMember power_user_activity_screen_dim_delay_factor_;
 
   DISALLOW_COPY_AND_ASSIGN(Preferences);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_PREFERENCES_H_