Don't add keep-alives for apps after the app keep-alive service has shut down.

apps/app_keep_alive_service.cc

 // Copyright 2013 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 "apps/app_keep_alive_service.h"
 
 #include "apps/app_lifetime_monitor.h"
 #include "apps/app_lifetime_monitor_factory.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile.h"
 
 namespace apps {
 
 AppKeepAliveService::AppKeepAliveService(content::BrowserContext* context)
-    : context_(context) {
+    : context_(context), shut_down_(false) {
   AppLifetimeMonitor* app_lifetime_monitor =
       AppLifetimeMonitorFactory::GetForProfile(static_cast<Profile*>(context));
   app_lifetime_monitor->AddObserver(this);
 }
 
 AppKeepAliveService::~AppKeepAliveService() {}
 
 void AppKeepAliveService::Shutdown() {
   AppLifetimeMonitor* app_lifetime_monitor =
       AppLifetimeMonitorFactory::GetForProfile(static_cast<Profile*>(context_));
   app_lifetime_monitor->RemoveObserver(this);
   OnChromeTerminating();
 }
 
 void AppKeepAliveService::OnAppStart(Profile* profile,
                                      const std::string& app_id) {
-  if (profile != context_)
+  if (profile != context_ || shut_down_)
     return;
 
   if (running_apps_.insert(app_id).second)
     chrome::StartKeepAlive();
 }
 
 void AppKeepAliveService::OnAppStop(Profile* profile,
                                     const std::string& app_id) {
   if (profile != context_)
     return;
 
   if (running_apps_.erase(app_id))
     chrome::EndKeepAlive();
 }
 
 void AppKeepAliveService::OnAppActivated(Profile* profile,
                                          const std::string& app_id) {}
 
 void AppKeepAliveService::OnAppDeactivated(Profile* profile,
                                            const std::string& app_id) {}
 
 void AppKeepAliveService::OnChromeTerminating() {
+  shut_down_ = true;
   size_t keep_alives = running_apps_.size();
   running_apps_.clear();
 
   // In some tests, the message loop isn't running during shutdown and ending
   // the last keep alive in that case CHECKs.
   if (!base::MessageLoop::current() ||
       base::MessageLoop::current()->is_running()) {
     while (keep_alives--)
       chrome::EndKeepAlive();
   }
 }
 
 }  // namespace apps