Add the copresence component.

components/copresence/public/copresence_client.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_PUBLIC_COPRESENCE_CLIENT_H_
+#define COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_CLIENT_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "components/copresence/proto/rpcs.pb.h"
+#include "components/copresence/public/copresence_client_delegate.h"
+
+namespace net {
+class URLContextGetter;
+}
+
+namespace copresence {
+
+class CopresenceClientDelegate;
+class RpcHandler;
+
+struct PendingRequest {
+  PendingRequest(const copresence::ReportRequest& report,
+                 const std::string app_id,
+                 const StatusCallback& callback);
+  ~PendingRequest();
+
+  copresence::ReportRequest report;
+  std::string app_id;
+  StatusCallback callback;
+};
+
+// The CopresenceClient class is the central interface for Copresence
+// functionality. This class handles all the initialization and delegation of
+// copresence tasks. Any user of copresence only needs to interact with this
+// client.
+class CopresenceClient : public base::SupportsWeakPtr<CopresenceClient> {
+ public:
+  // The delegate must outlive us.
+  explicit CopresenceClient(CopresenceClientDelegate* delegate);
+  virtual ~CopresenceClient();
+
+  // This method will execute a report request. Each report request can have
+  // multiple (un)publishes, (un)subscribes. This will ensure that once the
+  // client is initialized, it sends all request to the server and handles
+  // the response. If an error is encountered, the status callback is used
+  // to relay it to the requester.
+  void ExecuteReportRequest(copresence::ReportRequest request,
+                            const std::string& app_id,
+                            const StatusCallback& callback);
+
+  // Called before the API (and thus the Client) is destructed.
+  void Shutdown();
+
+ private:
+  void CompleteInitialization();
+  void InitStepComplete(const std::string& step, bool success);
+
+  CopresenceClientDelegate* delegate_;
+  bool init_failed_;
+  std::vector<PendingRequest> pending_requests_queue_;
+
+  // TODO(rkc): This code is almost identical to what we use in feedback to
+  // perform multiple blocking tasks and then run a post process method. Look
+  // into refactoring it all out to a common construct, like maybe a
+  // PostMultipleTasksAndReply?
+  size_t pending_init_operations_;
+
+  scoped_ptr<RpcHandler> rpc_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(CopresenceClient);
+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_CLIENT_H_