CrOS: Do not allow notifications to be added during shutdown.

chrome/browser/notifications/message_center_notification_manager.cc

Index: chrome/browser/notifications/message_center_notification_manager.cc
diff --git a/chrome/browser/notifications/message_center_notification_manager.cc b/chrome/browser/notifications/message_center_notification_manager.cc
index e60cdd6f8c11a0a9b8e80ab4bde751eb77425501..42313f9ea4a1b5c010f6f5071eebb5393f55e817 100644
--- a/chrome/browser/notifications/message_center_notification_manager.cc
+++ b/chrome/browser/notifications/message_center_notification_manager.cc
@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "build/build_config.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/notifications/extension_welcome_notification.h"
 #include "chrome/browser/notifications/extension_welcome_notification_factory.h"
 #include "chrome/browser/notifications/fullscreen_notification_blocker.h"
@@ -80,6 +81,10 @@ MessageCenterNotificationManager::~MessageCenterNotificationManager() {
 
 void MessageCenterNotificationManager::Add(const Notification& notification,

[sky, 2017/03/28 22:00:34]

Would it make more sense for this class to be destroyed earlier on, so that you
never end up during shutdown?

[sammiequon, 2017/03/28 23:12:08]

It would, but would this cause a bunch of other bugs? Also I'm not 100% certain
this will fix the crash. If I were to destroy this class early I would do it at
[1]? and then change all instances to check if the notification_manager() exists
before using it?

[1]
https://cs.chromium.org/chromium/src/chrome/browser/lifetime/application_life...

[stevenjb, 2017/03/29 00:21:33]

I would also be worried about dereferencing errors. We have a lot of calls (36)
to g_browser_process->notification_ui_manager() in the code. This seems like a
reasonable approach to me.

                                            Profile* profile) {
+  // We won't have time to process and act on this notification.
+  if (g_browser_process->IsShuttingDown())
+    return;
+
   if (Update(notification, profile))
     return;