Keep browser process alive while there are platform apps with background pages running.

chrome/browser/profiles/profile_dependency_manager.cc

Index: chrome/browser/profiles/profile_dependency_manager.cc
diff --git a/chrome/browser/profiles/profile_dependency_manager.cc b/chrome/browser/profiles/profile_dependency_manager.cc
index 282d5a8d30a3aa248331c5840bac41cb142d9433..9488ff6728b883a56be972534a73407b9d97fc67 100644
--- a/chrome/browser/profiles/profile_dependency_manager.cc
+++ b/chrome/browser/profiles/profile_dependency_manager.cc
@@ -23,6 +23,7 @@
 #include "chrome/browser/extensions/api/tab_capture/tab_capture_registry_factory.h"
 #include "chrome/browser/extensions/app_restore_service_factory.h"
 #include "chrome/browser/extensions/extension_system_factory.h"
+#include "chrome/browser/extensions/platform_app_service_factory.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/google/google_url_tracker_factory.h"
 #include "chrome/browser/history/history_service_factory.h"
@@ -225,6 +226,7 @@ void ProfileDependencyManager::AssertFactoriesBuilt() {
   extensions::CommandServiceFactory::GetInstance();
   extensions::ExtensionSystemFactory::GetInstance();
   extensions::IdleManagerFactory::GetInstance();
+  extensions::PlatformAppServiceFactory::GetInstance();
   extensions::ProcessesAPIFactory::GetInstance();
   extensions::SuggestedLinksRegistryFactory::GetInstance();
   extensions::TabCaptureRegistryFactory::GetInstance();