Adding the Copresence RpcHandler and HttpPost helper.

components/copresence/rpc/http_post.h

+// Copyright 2014 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_COPRESENCE_RPC_HTTP_POST_H_
+#define COMPONENTS_COPRESENCE_RPC_HTTP_POST_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/url_request/url_fetcher_delegate.h"
+
+namespace google {
+namespace protobuf {
+class MessageLite;
+}
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace copresence {
+
+// This class handles all Apiary calls to the Copresence server.
+// It configures the HTTP request appropriately and reports any errors.
+// If deleted, the HTTP request is cancelled.
+//
+// TODO(ckehoe): Add retry logic.
+class HttpPost : public net::URLFetcherDelegate {
+ public:
+  // Callback to receive the HTTP status code and body of the response
+  // (if any). A pointer to this HttpPost object is also passed along.
+  typedef base::Callback<void(int, const std::string&)>
+      ResponseCallback;
+
+  // An id for testing url fetching.
+  static const int kUrlFetcherId = 1;
+
+  // The query parameter to send Apiary tracing tokens.
+  static const char kTracingTokenField[];
+
+  // Create a request to the Copresence server. |url_context_getter|
+  // is owned by the caller, and the context it provides must be available
+  // until the request completes.
+  HttpPost(net::URLRequestContextGetter* url_context_getter,
+           const std::string& server_host,
+           const std::string& rpc_name,
+           const std::string& tracing_token,
+           const google::protobuf::MessageLite& request_proto);
+
+  // HTTP requests are cancelled on delete.
+  virtual ~HttpPost();
+
+  // Send an HttpPost request.
+  void Start(const ResponseCallback& response_callback);
+
+ private:
+  // Overridden from net::URLFetcherDelegate.
+  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
+
+  ResponseCallback response_callback_;
+  scoped_ptr<net::URLFetcher> url_fetcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(HttpPost);
+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_RPC_HTTP_POST_H_