Refactoring: Moving the SafeJsonParser to its own component.

components/safe_json_parser/safe_json_parser_message_filter.h

Index: components/safe_json_parser/safe_json_parser_message_filter.h
diff --git a/components/safe_json_parser/safe_json_parser_message_filter.h b/components/safe_json_parser/safe_json_parser_message_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..f0b061dcc45c4ac5a8fa83140657687265ad9c3c
--- /dev/null
+++ b/components/safe_json_parser/safe_json_parser_message_filter.h
@@ -0,0 +1,38 @@
+// 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_PARSER_SAFE_JSON_PARSER_MESSAGE_FILTER_H_
+#define COMPONENTS_SAFE_JSON_PARSER_SAFE_JSON_PARSER_MESSAGE_FILTER_H_
+
+#include <string>
+
+#include "base/macros.h"
+
+namespace IPC {
+class Message;
+}  // namespace IPC
+
+namespace safe_json_parser {
+
+// A Handler for the ParseJSON IPC message that does the actual JSON parsing
+// in the sandboxed process. Modelled after IPC::MessageFilter but does not
+// directly implement it as it will be used by an adapter class under
+// //chrome/utility.
+class SafeJsonParserMessageFilter {

[jam, 2015/05/18 23:59:19]

why does this not derive from IPC::MessageFilter?

I don't understandy why chrome/utility/utility_message_handler.h exists in the
first place instead of that just using IPC::MessageFilter interface

[Eran Messeri, 2015/05/19 20:49:56]

It doesn't derive from IPC::MessageFilter because it's not added as a filter to
any IPC ChannelProxy. It wouldn't conform to the interface's intentions if this
class derived from IPC::MessageFilter since it's used by the
UtilityMessageHandler which will only delegate OnMessageReceived. It would be
deceptive to derive from IPC::MessageFilter here since no other interface method
would be called.

Maybe vitalybuka@ can explain the reason for the existence of
UtilityMessageHandler.

[jam, 2015/05/20 15:38:31]

ok.

+ public:
+  SafeJsonParserMessageFilter();
+  ~SafeJsonParserMessageFilter();
+  // Returns true if it receives a message it could handle (currently
+  // only SafeJsonParserMsg_ParseJSON), false otherwise.
+  bool OnMessageReceived(const IPC::Message& message);
+
+ private:
+  void OnParseJSON(const std::string& json);
+
+  DISALLOW_COPY_AND_ASSIGN(SafeJsonParserMessageFilter);
+};
+
+}  // namespace safe_json_parser
+
+#endif  // COMPONENTS_SAFE_JSON_PARSER_SAFE_JSON_PARSER_MESSAGE_FILTER_H_