Migrate upgrade notifications to observer

chrome/browser/service_process/service_process_control.cc

 // Copyright (c) 2012 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/service_process/service_process_control.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_delta_serialization.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/task_scheduler/post_task.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/upgrade_detector.h"
 #include "chrome/common/service_messages.h"
 #include "chrome/common/service_process_util.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/notification_service.h"
 #include "ipc/ipc_channel_mojo.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/embedder/named_platform_handle.h"
 #include "mojo/edk/embedder/named_platform_handle_utils.h"
 #include "mojo/edk/embedder/peer_connection.h"
 
 using content::BrowserThread;
 
 namespace {
 
@@ skipping 36 matching lines @@
         std::move(handle));
     response_task_runner->PostTask(FROM_HERE,
                                    base::BindOnce(std::move(response_callback),
                                                   std::move(peer_connection)));
   }
 }
 
 }  // namespace
 
 // ServiceProcessControl implementation.
-ServiceProcessControl::ServiceProcessControl() : weak_factory_(this) {}
+ServiceProcessControl::ServiceProcessControl() : weak_factory_(this) {
+  UpgradeDetector::GetInstance()->AddObserver(this);
+}
 
 ServiceProcessControl::~ServiceProcessControl() {
+  UpgradeDetector::GetInstance()->RemoveObserver(this);
 }
 
 void ServiceProcessControl::ConnectInternal() {
   // If the channel has already been established then we run the task
   // and return.
   if (channel_.get()) {
     RunConnectDoneTasks();
     return;
   }
 
@@ skipping 134 matching lines @@
 void ServiceProcessControl::OnChannelConnected(int32_t peer_pid) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   UMA_HISTOGRAM_ENUMERATION("CloudPrint.ServiceEvents",
                             SERVICE_EVENT_CHANNEL_CONNECTED, SERVICE_EVENT_MAX);
 
   // We just established a channel with the service process. Notify it if an
   // upgrade is available.
   if (UpgradeDetector::GetInstance()->notify_upgrade()) {
     Send(new ServiceMsg_UpdateAvailable);
-  } else {
-    if (registrar_.IsEmpty())
-      registrar_.Add(this, chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
-                     content::NotificationService::AllSources());
   }
   RunConnectDoneTasks();
 }
 
 void ServiceProcessControl::OnChannelError() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   UMA_HISTOGRAM_ENUMERATION("CloudPrint.ServiceEvents",
                             SERVICE_EVENT_CHANNEL_ERROR, SERVICE_EVENT_MAX);
 
   channel_.reset();
   peer_connection_.reset();
   RunConnectDoneTasks();
 }
 
 bool ServiceProcessControl::Send(IPC::Message* message) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!channel_.get())
     return false;
   return channel_->Send(message);
 }
 
-// content::NotificationObserver implementation.
-void ServiceProcessControl::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_UPGRADE_RECOMMENDED, type);

[sky, 2017/06/07 23:01:41]

Previously the observer was only added in a certain cases. Don't you need to
protect against that? By that I mean either set some boolean around line 248
(old) or conditionally add the observer?

[weidongg, 2017/06/08 02:28:42]

This function will be called multiple times. So I added a
|enable_upgrade_observer_| to prevent duplicate adding observer.

+void ServiceProcessControl::OnUpgradeRecommended() {
   Send(new ServiceMsg_UpdateAvailable);
 }
 
 void ServiceProcessControl::OnCloudPrintProxyInfo(
     const cloud_print::CloudPrintProxyInfo& proxy_info) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   UMA_HISTOGRAM_ENUMERATION("CloudPrint.ServiceEvents",
                             SERVICE_EVENT_INFO_REPLY, SERVICE_EVENT_MAX);
   if (!cloud_print_info_callback_.is_null()) {
     cloud_print_info_callback_.Run(proxy_info);
@@ skipping 166 matching lines @@
   if (process_.IsValid()) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&Launcher::DoDetectLaunched, this));
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE, base::Bind(&Launcher::Notify, this));
   }
 }
 #endif  // !OS_MACOSX