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

components/offline_pages/core/prefetch/prefetch_service_impl.cc

Index: components/offline_pages/core/prefetch/prefetch_service_impl.cc
diff --git a/components/offline_pages/core/prefetch/prefetch_service_impl.cc b/components/offline_pages/core/prefetch/prefetch_service_impl.cc
index 13f0eb3f40502706ad1a1fe7f2d6503c5f811f87..330a6b230d09c8ea929a4ca1b08dce0d25c5ee9a 100644
--- a/components/offline_pages/core/prefetch/prefetch_service_impl.cc
+++ b/components/offline_pages/core/prefetch/prefetch_service_impl.cc
@@ -32,6 +32,32 @@ void PrefetchServiceImpl::StopBackgroundTask(ScopedBackgroundTask* task) {
   NOTIMPLEMENTED();
 }
 
+void PrefetchServiceImpl::ShutdownHandler() {}
+
+void PrefetchServiceImpl::OnStoreReset() {}
+
+void PrefetchServiceImpl::OnMessage(const std::string& app_id,
+                                    const gcm::IncomingMessage& message) {
+  DVLOG(1) << "PrefetchServiceImpl " << __func__ << ":" << message.raw_data;
+}
+
+void PrefetchServiceImpl::OnMessagesDeleted(const std::string& app_id) {
+  NOTIMPLEMENTED();
+}
+
+void PrefetchServiceImpl::OnSendError(
+    const std::string& app_id,
+    const gcm::GCMClient::SendErrorDetails& send_error_details) {
+  // We should never get here, since we are not sending GCM upstream.
+  NOTREACHED();
+}
+
+void PrefetchServiceImpl::OnSendAcknowledged(const std::string& app_id,
+                                             const std::string& message_id) {
+  // We should never get here, since we are not sending GCM upstream.
+  NOTREACHED();
+}
+
 void PrefetchServiceImpl::Shutdown() {}
 
 }  // namespace offline_pages