Split ValueSerializer into separate Serializer and Deserializer classes.

base/values.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.
 
 // This file specifies a recursive data storage class called Value intended for
 // storing settings and other persistable data.
 //
 // A Value represents something that can be stored in JSON or passed to/from
 // JavaScript. As such, it is NOT a generalized variant type, since only the
 // types supported by JavaScript/JSON are supported.
@@ skipping 474 matching lines @@
   bool GetAsList(const ListValue** out_value) const override;
   ListValue* DeepCopy() const override;
   bool Equals(const Value* other) const override;
 
  private:
   ValueVector list_;
 
   DISALLOW_COPY_AND_ASSIGN(ListValue);
 };
 
-// This interface is implemented by classes that know how to serialize and
-// deserialize Value objects.
+// This interface is implemented by classes that know how to serialize
+// Value objects.
 class BASE_EXPORT ValueSerializer {
  public:
   virtual ~ValueSerializer();
 
   virtual bool Serialize(const Value& root) = 0;
+};
+
+// This interface is implemented by classes that know how to deserialize Value
+// objects.
+class BASE_EXPORT ValueDeserializer {
+ public:
+  virtual ~ValueDeserializer();
 
   // This method deserializes the subclass-specific format into a Value object.
   // If the return value is non-NULL, the caller takes ownership of returned
   // Value. If the return value is NULL, and if error_code is non-NULL,
   // error_code will be set with the underlying error.
   // If |error_message| is non-null, it will be filled in with a formatted
   // error message including the location of the error if appropriate.
   virtual Value* Deserialize(int* error_code, std::string* error_str) = 0;
 };
 
@@ skipping 19 matching lines @@
 }
 
 BASE_EXPORT inline std::ostream& operator<<(std::ostream& out,
                                             const ListValue& value) {
   return out << static_cast<const Value&>(value);
 }
 
 }  // namespace base
 
 #endif  // BASE_VALUES_H_