[Offline Pages] Add a GCMAppHandler for offline page prefetch.

components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h

Index: components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h
diff --git a/components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h b/components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..582aa0f6cae1780a38ca907e479e6ab62e195a5a
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+++ b/components/offline_pages/core/prefetch/prefetch_gcm_app_handler.h
@@ -0,0 +1,50 @@
+// Copyright 2017 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_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_APP_HANDLER_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_APP_HANDLER_H_
+
+#include <string>
+
+#include "components/gcm_driver/common/gcm_messages.h"
+#include "components/gcm_driver/gcm_app_handler.h"
+#include "components/gcm_driver/gcm_driver.h"
+#include "components/offline_pages/core/prefetch/prefetch_service.h"
+#include "components/offline_pages/core/prefetch/prefetch_service_impl.h"
+#include "url/gurl.h"
+
+namespace offline_pages {
+
+// Receives GCM messages and other channel status messages on behalf of the
+// prefetch system.
+class PrefetchGCMAppHandler : public gcm::GCMAppHandler,
+                              public PrefetchServiceImpl::GCMAppHandler {
+ public:
+  PrefetchGCMAppHandler();
+  ~PrefetchGCMAppHandler() override;
+
+  // gcm::GCMAppHandler implementation.
+  void ShutdownHandler() override;
+  void OnStoreReset() override;
+  void OnMessage(const std::string& app_id,
+                 const gcm::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;
+
+  const std::string& app_id() const { return app_id_; }
+
+ private:
+  std::string app_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrefetchGCMAppHandler);
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_APP_HANDLER_H_