Make JSONParser a pure interface.

components/safe_json/testing_json_parser.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_TESTING_JSON_PARSER_H_
+#define COMPONENTS_SAFE_JSON_TESTING_JSON_PARSER_H_
+
+#include "components/safe_json/safe_json_parser.h"
+
+namespace safe_json {
+
+// An implementation of SafeJsonParser that parses JSON in process. This can be
+// used in unit tests to avoid having to set up the multiprocess infrastructure
+// necessary for the out-of-process SafeJsonParser.
+class TestingJsonParser : public SafeJsonParser {
+ public:
+  // A helper class that will temporarily override the SafeJsonParser factory to
+  // create instances of this class.
+  class ScopedFactoryOverride {
+   public:
+    ScopedFactoryOverride();
+    ~ScopedFactoryOverride();
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(ScopedFactoryOverride);
+  };
+
+  // If instantiating this class manually, it must be allocated with |new| (i.e.
+  // not on the stack). It will delete itself after calling one of the
+  // callbacks.
+  TestingJsonParser(const std::string& unsafe_json,
+                    const SuccessCallback& success_callback,
+                    const ErrorCallback& error_callback);
+  ~TestingJsonParser() override;
+
+ private:
+  void Start() override;
+
+  const std::string unsafe_json_;
+  SuccessCallback success_callback_;
+  ErrorCallback error_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestingJsonParser);
+};
+
+}  // namespace
+
+#endif  // COMPONENTS_SAFE_JSON_TESTING_JSON_PARSER_H_