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

chrome/browser/offline_pages/prefetch/prefetch_gcm_app_handler.cc

+// 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.
+
+#include "chrome/browser/offline_pages/prefetch/prefetch_gcm_app_handler.h"
+
+namespace offline_pages {
+namespace {
+const char kPrefetchingOfflinePagesAppId[] =
+    "com.google.chrome.OfflinePagePrefetch";
+}
+
+PrefetchGCMAppHandler::PrefetchGCMAppHandler()
+    : app_id_(kPrefetchingOfflinePagesAppId) {}
+PrefetchGCMAppHandler::~PrefetchGCMAppHandler() = default;
+
+void PrefetchGCMAppHandler::ShutdownHandler() {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchGCMAppHandler::OnStoreReset() {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchGCMAppHandler::OnMessage(const std::string& app_id,
+                                      const gcm::IncomingMessage& message) {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchGCMAppHandler::OnMessagesDeleted(const std::string& app_id) {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchGCMAppHandler::OnSendError(
+    const std::string& app_id,
+    const gcm::GCMClient::SendErrorDetails& send_error_details) {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchGCMAppHandler::OnSendAcknowledged(const std::string& app_id,
+                                               const std::string& message_id) {
+  NOTIMPLEMENTED();
+}
+
+bool PrefetchGCMAppHandler::CanHandle(const std::string& app_id) const {
+  return app_id == app_id_;
+}
+
+}  // namespace offline_pages