Add touchpad speed factor setting to Chrome OS touchpad settings page...

chrome/browser/chromeos/touchpad.h

 // Copyright (c) 2006-2008 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_TOUCHPAD_H_
 #define CHROME_BROWSER_CHROMEOS_TOUCHPAD_H_
 
 #include <string>
 
 #include "chrome/common/notification_observer.h"
 #include "chrome/common/pref_member.h"
 
 class PrefService;
 
 // The Touchpad class handles touchpad preferences. When the class is first
 // initialized, it will initialize the touchpad settings to what's stored in the
 // preferences. And whenever the preference changes, we change the touchpad
 // setting to reflect the new value.
 //
 // For Synaptics touchpads, we use synclient to change settings on-the-fly.
-// See "man synaptics" for a list of settings that can be changed
+// See "man synaptics" for a list of settings that can be changed.
 // Since we are doing a system call to run the synclient binary, we make sure
-// that we are running on the IO thread so that we don't block the UI thread.
+// that we are running on the File thread so that we don't block the UI thread.
 class Touchpad : public NotificationObserver {
  public:
   explicit Touchpad() {}
   virtual ~Touchpad() {}
 
   // This method will register the prefs associated with touchpad settings.
   static void RegisterUserPrefs(PrefService* prefs);
 
   // This method will initialize touchpad settings to values in user prefs.
   virtual void Init(PrefService* prefs);
 
   // Overridden from NotificationObserver:
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
  protected:
   virtual void NotifyPrefChanged(const std::wstring* pref_name);
 
  private:
   // This methods makes a system call to synclient to change touchpad settings.
   // The system call will be invoked on the file thread.
   void SetSynclientParam(const std::string& param, const std::string& value);
 
+  // Set tap-to-click to value stored in preference.
   void SetTapToClick();
+
+  // Set vertical edge scrolling to value stored in preference.
   void SetVertEdgeScroll();
 
+  // Set touchpad speed factor to value stored in preference.
+  void SetSpeedFactor();
+
   BooleanPrefMember tap_to_click_enabled_;
   BooleanPrefMember vert_edge_scroll_enabled_;
+  RealPrefMember speed_factor_;
 
   DISALLOW_COPY_AND_ASSIGN(Touchpad);
 };
 
 #endif  // CHROME_BROWSER_CHROMEOS_TOUCHPAD_H_