Add ClientConfig proto, and JSON generation/parsing.

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_client.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_config_client.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_client.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..bf2d4c21484c6712c5c2234ee5d287207f7f1f3c
--- /dev/null
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_client.h
@@ -0,0 +1,52 @@
+// 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_BROWSER_DATA_REDUCTION_PROXY_CONFIG_CLIENT_H_
+#define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_CLIENT_H_
+
+#include <string>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+class DictionaryValue;

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

Remove unused forward declaration

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

Done.

+}
+
+namespace data_reduction_proxy {
+
+class DataReductionProxyParams;
+class DataReductionProxyRequestOptions;
+
+// Retrieves the Data Reduction Proxy configuration from a remote service. This
+// objects lives on the IO thread.

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

nit: s/objects/object/

[jeremyim, 2015/03/20 16:21:10]

Done.

+class DataReductionProxyConfigClient {

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

"ConfigClient" seems a bit ambiguous, maybe "ConfigFetcher" instead if it's just
retrieving the config?

Otherwise we have both "ConfigClient" and "ClientConfig".

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

Done.

+ public:
+  // The caller must ensure that all parameters remain alive for the lifetime of
+  // the |DataReductionProxyConfigClient|.
+  DataReductionProxyConfigClient(

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

This class doesn't have any public methods, and the constructor does nothing.
Why add an empty class? What is it supposed to do in the future? Why not just
add this class later along with it's functionality?

[jeremyim, 2015/03/20 16:21:10]

The next CL is already pretty large; the more I can move into this CL that is
fairly self-contained makes the future easier.

+      DataReductionProxyParams* params,
+      DataReductionProxyRequestOptions* request_options);
+
+  virtual ~DataReductionProxyConfigClient();

[bengr, 2015/03/19 16:31:14]

Does this need to be virtual?

[jeremyim, 2015/03/20 16:21:10]

Done.

+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(DataReductionProxyConfigClientTest,
+                           TestConstructStaticResponse);
+
+  // Constructs a synthetic response based on |params_|.

[bengr, 2015/03/19 16:31:14]

Why is it 'synthetic'?

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

It is synthetic in that it is locally manufactured, and not from the service.

+  std::string ConstructStaticResponse();
+
+  // The caller must ensure that the |params_| outlives this instance.
+  DataReductionProxyParams* params_;
+
+  // The caller must ensure that the |request_options_| outlives this instance.
+  DataReductionProxyRequestOptions* request_options_;
+
+  DISALLOW_COPY_AND_ASSIGN(DataReductionProxyConfigClient);
+};
+
+}  // namespace data_reduction_proxy
+#endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_CLIENT_H_