Convert //components/prefs from scoped_ptr to std::unique_ptr

components/prefs/default_pref_store.h

Index: components/prefs/default_pref_store.h
diff --git a/components/prefs/default_pref_store.h b/components/prefs/default_pref_store.h
index 2e338899beacbbea6070110de1e3f56198184672..3481713f8935afaf60a5ee7e3d09bf1f057e1fb6 100644
--- a/components/prefs/default_pref_store.h
+++ b/components/prefs/default_pref_store.h
@@ -30,12 +30,13 @@ class COMPONENTS_PREFS_EXPORT DefaultPrefStore : public PrefStore {
 
   // Sets a |value| for |key|. Should only be called if a value has not been
   // set yet; otherwise call ReplaceDefaultValue().
-  void SetDefaultValue(const std::string& key, scoped_ptr<base::Value> value);
+  void SetDefaultValue(const std::string& key,
+                       std::unique_ptr<base::Value> value);
 
   // Replaces the the value for |key| with a new value. Should only be called
   // if a value has alreday been set; otherwise call SetDefaultValue().
   void ReplaceDefaultValue(const std::string& key,
-                           scoped_ptr<base::Value> value);
+                           std::unique_ptr<base::Value> value);
 
   const_iterator begin() const;
   const_iterator end() const;