Remove NOTIMPLEMENTED from PrefetchGCMAppHandler.

Bug: 1020341
Change-Id: I90fd34199754b53585014118b6fefece37e3ccf4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894395Reviewed-by: Dan H <harringtond@chromium.org>
Commit-Queue: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711690}

components/offline_pages/core/prefetch/prefetch_gcm_app_handler.cc

@@ -21,13 +21,9 @@ void PrefetchGCMAppHandler::SetService(PrefetchService* service) {
   prefetch_service_ = service;
 }
 
-void PrefetchGCMAppHandler::ShutdownHandler() {
-  NOTIMPLEMENTED();
-}
+void PrefetchGCMAppHandler::ShutdownHandler() {}
 
-void PrefetchGCMAppHandler::OnStoreReset() {
-  NOTIMPLEMENTED();
-}
+void PrefetchGCMAppHandler::OnStoreReset() {}
 
 void PrefetchGCMAppHandler::OnMessage(const std::string& app_id,
                                       const gcm::IncomingMessage& message) {
@@ -48,20 +44,14 @@ void PrefetchGCMAppHandler::OnMessage(const std::string& app_id,
       "; pageBundle data: " + pageBundle);
 }
 
-void PrefetchGCMAppHandler::OnMessagesDeleted(const std::string& app_id) {
-  NOTIMPLEMENTED();
-}
+void PrefetchGCMAppHandler::OnMessagesDeleted(const std::string& app_id) {}
 
 void PrefetchGCMAppHandler::OnSendError(
     const std::string& app_id,
-    const gcm::GCMClient::SendErrorDetails& send_error_details) {
-  NOTIMPLEMENTED();
-}
+    const gcm::GCMClient::SendErrorDetails& send_error_details) {}
 
 void PrefetchGCMAppHandler::OnSendAcknowledged(const std::string& app_id,
-                                               const std::string& message_id) {
-  NOTIMPLEMENTED();
-}
+                                               const std::string& message_id) {}
 
 bool PrefetchGCMAppHandler::CanHandle(const std::string& app_id) const {
   return app_id == GetAppId();