components: Cleanup class/struct fwd declarations

components/safe_json/safe_json_parser_android.h

 // Copyright 2015 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 COMPONENTS_SAFE_JSON_SAFE_JSON_PARSER_ANDROID_H_
 #define COMPONENTS_SAFE_JSON_SAFE_JSON_PARSER_ANDROID_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/safe_json/safe_json_parser.h"
 
 namespace safe_json {
 
-class JsonSanitizer;
-
 class SafeJsonParserAndroid : public SafeJsonParser {
  public:
   SafeJsonParserAndroid(const std::string& unsafe_json,
                         const SuccessCallback& success_callback,
                         const ErrorCallback& error_callback);
 
  private:
   friend std::default_delete<SafeJsonParserAndroid>;
 
   ~SafeJsonParserAndroid() override;
 
   void OnSanitizationSuccess(const std::string& sanitized_json);
   void OnSanitizationError(const std::string& error);
 
   // SafeJsonParser implementation.
   void Start() override;
 
   const std::string unsafe_json_;
   SuccessCallback success_callback_;
   ErrorCallback error_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SafeJsonParserAndroid);
 };
 
 }  // namespace safe_json
 
 #endif   // COMPONENTS_SAFE_JSON_SAFE_JSON_PARSER_ANDROID_H_