Undoing revert, cl is not the cause of gcm crash on canary.

components/copresence/handlers/gcm_handler.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_HANDLERS_GCM_HANDLER_H_
+#define COMPONENTS_COPRESENCE_HANDLERS_GCM_HANDLER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "components/gcm_driver/gcm_app_handler.h"
+#include "components/gcm_driver/gcm_client.h"
+
+namespace gcm {
+class GCMDriver;
+}
+
+namespace copresence {
+
+class DirectiveHandler;
+
+// This class handles GCM messages from the Copresence server.
+class GCMHandler final : public gcm::GCMAppHandler,
+                         public base::SupportsWeakPtr<GCMHandler> {
+ public:
+  // Callback to report that registration has completed.
+  // Returns an empty ID if registration failed.
+  using RegistrationCallback = base::Callback<void(const std::string&)>;
+
+  static const char kCopresenceAppId[];
+  static const char kCopresenceSenderId[];
+  static const char kGcmMessageKey[];
+
+  // |gcm_driver| is required, but may disappear if we get a ShutdownHandler()
+  // call first. |directive_handler| must outlive us. The caller owns both.
+  GCMHandler(gcm::GCMDriver* gcm_driver,
+             DirectiveHandler* directive_handler);
+  ~GCMHandler() override;
+
+  // Request the GCM ID. It may be returned now or later, via the callback.
+  void GetGcmId(const RegistrationCallback& callback);
+
+  // GCMAppHandler overrides
+  void ShutdownHandler() override;
+  void OnMessage(const std::string& app_id,
+                 const gcm::GCMClient::IncomingMessage& message) override;
+  void OnMessagesDeleted(const std::string& app_id) override;
+  void OnSendError(
+      const std::string& /* app_id */,
+      const gcm::GCMClient::SendErrorDetails& /* send_error_details */)
+      override;
+  void OnSendAcknowledged(const std::string& /* app_id */,
+                          const std::string& /* message_id */) override;
+  bool CanHandle(const std::string& app_id) const override;
+
+ private:
+  // GCM Registration has finished. Notify clients as appropriate.
+  void RegistrationComplete(const std::string& registration_id,
+                            gcm::GCMClient::Result result);
+
+  gcm::GCMDriver* driver_;
+  DirectiveHandler* const directive_handler_;
+
+  // TODO(ckehoe): Change this to a CancelableCallback.
+  base::Callback<void(const std::string&,
+                      gcm::GCMClient::Result)> registration_callback_;
+
+  std::string gcm_id_;
+  std::vector<RegistrationCallback> pending_id_requests_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMHandler);
+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_HANDLERS_GCM_HANDLER_H_