Add ClientConfig proto, and JSON generation/parsing.

components/data_reduction_proxy/core/common/client_config_parser.h

Index: components/data_reduction_proxy/core/common/client_config_parser.h
diff --git a/components/data_reduction_proxy/core/common/client_config_parser.h b/components/data_reduction_proxy/core/common/client_config_parser.h
new file mode 100644
index 0000000000000000000000000000000000000000..308762c21ba093a064394c66e3cd4de68077676d
--- /dev/null
+++ b/components/data_reduction_proxy/core/common/client_config_parser.h
@@ -0,0 +1,44 @@
+// 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_DATA_REDUCTION_PROXY_CORE_COMMON_CLIENT_CONFIG_RESPONSE_PARSER_H_
+#define COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_CLIENT_CONFIG_RESPONSE_PARSER_H_
+
+#include <string>
+
+#include "components/data_reduction_proxy/proto/client_config.pb.h"
+#include "net/proxy/proxy_server.h"
+
+namespace base {
+class Time;
+}
+
+namespace data_reduction_proxy {
+
+// Returns a string representation (which is actually the string representation
+// of ProxyServer_ProxyScheme) of a |net::ProxyServer::Scheme|.
+std::string GetSchemeString(net::ProxyServer::Scheme scheme);
+
+// Returns the |net::ProxyServer::Scheme| for a ProxyServer_ProxyScheme.
+net::ProxyServer::Scheme SchemeFromProxyScheme(
+    ProxyServer_ProxyScheme proxy_scheme);
+
+// Retrieves the ProxyServer_ProxyScheme for its string representation.
+ProxyServer_ProxyScheme GetProxyScheme(const std::string& scheme);
+
+// Returns the ISO-8601 representation of |time|.
+std::string TimeToISO8601(const base::Time& time);
+
+// Parses an ISO-8601 time string into a Timestamp proto.
+bool ISO8601ToTimestamp(const std::string& time, Timestamp* timestamp);
+
+// Returns the |base::Time| representation of |timestamp|.
+base::Time TimestampToTime(const Timestamp& timestamp);
+
+// Takes a JSON representation of a |ClientConfig| and populates |config|.
+// Returns false if the JSON has an unexpected structure.

[sclittle, 2015/03/18 20:31:51]

I'm confused. You turn a JSON into a proto; why do you want to do this? If
you're using a JSON over the wire, then why use a proto at all?

[bengr, 2015/03/19 16:31:15]

I agree that some explanation is in order. Please add a comment somewhere.

[jeremyim, 2015/03/20 16:21:11]

Done.

+bool ParseClientConfig(const std::string& config_data, ClientConfig* config);
+}  // namespace data_reduction_proxy
+
+#endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_CLIENT_CONFIG_RESPONSE_PARSER_H_