Revert recent changes to base::Value

chrome/test/webdriver/commands/response.h

 // Copyright (c) 2011 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_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_
 
 #include <sstream>
 #include <string>
 
@@ skipping 10 matching lines @@
  public:
   // Creates a new |Response| with a default status of |kSuccess| and a
   // |NullValue|.
   Response();
   ~Response();
 
   ErrorCode GetStatus() const;
   void SetStatus(ErrorCode status);
 
   // Ownership of the returned pointer is kept by this object.
-  Value* GetValue() const;
+  const Value* GetValue() const;
 
   // Sets the |value| of this response, assuming ownership of the object in the
   // process.
   void SetValue(Value* value);
 
   // Configures this response to report the given error. Ownership of the error
   // is taken from the caller.
   void SetError(Error* error);
 
   // Sets a JSON field in this response. The |key| may be a "." delimitted
   // string to indicate the value should be set in a nested object. Any
   // previously set value for the |key| will be deleted.
   // This object assumes ownership of |value|.
   void SetField(const std::string& key, Value* value);
 
   // Returns this response as a JSON string.
   std::string ToJSON() const;
 
  private:
   DictionaryValue data_;
 
   DISALLOW_COPY_AND_ASSIGN(Response);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_