Convert //chrome/browser/chromeos from scoped_ptr to std::unique_ptr

chrome/browser/chromeos/power/power_prefs.h

Index: chrome/browser/chromeos/power/power_prefs.h
diff --git a/chrome/browser/chromeos/power/power_prefs.h b/chrome/browser/chromeos/power/power_prefs.h
index 3f576ab420f28b316205a3a0422347776e50ad8e..d1a23a55c482d1f8e9364c54b0ff3497d15f819c 100644
--- a/chrome/browser/chromeos/power/power_prefs.h
+++ b/chrome/browser/chromeos/power/power_prefs.h
@@ -5,9 +5,10 @@
 #ifndef CHROME_BROWSER_CHROMEOS_POWER_POWER_PREFS_H_
 #define CHROME_BROWSER_CHROMEOS_POWER_POWER_PREFS_H_
 
+#include <memory>
+
 #include "base/compiler_specific.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
@@ -58,7 +59,7 @@ class PowerPrefs : public content::NotificationObserver {
   content::NotificationRegistrar notification_registrar_;
 
   Profile* profile_;  // Not owned.
-  scoped_ptr<PrefChangeRegistrar> pref_change_registrar_;
+  std::unique_ptr<PrefChangeRegistrar> pref_change_registrar_;
 
   // True while the screen is locked (but not while the login screen is shown).
   bool screen_is_locked_;