Introduce ArcServiceManager::OnShutdown().

chrome/browser/chromeos/extensions/file_manager/event_router.cc

Index: chrome/browser/chromeos/extensions/file_manager/event_router.cc
diff --git a/chrome/browser/chromeos/extensions/file_manager/event_router.cc b/chrome/browser/chromeos/extensions/file_manager/event_router.cc
index fe12c7bc18667d6e31f32679552819b7d5d7a3e4..b5d8605ab6ddcebac05b50b513bc0c8332ad1305 100644
--- a/chrome/browser/chromeos/extensions/file_manager/event_router.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/event_router.cc
@@ -401,6 +401,11 @@ EventRouter::EventRouter(Profile* profile)
 
 EventRouter::~EventRouter() = default;
 
+void EventRouter::OnArcShutdown() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[Shuhei Takahashi, 2016/12/16 13:36:13]

DCHECK_CURRENTLY_ON() is better because it can leave the log which thread it was
actually on on the failure.

Maybe you followed OnIntentFilteredUpdated(), but DCHECK_CURRENTLY_ON is used
everywhere except it. Strange...

[hidehiko, 2016/12/16 17:14:17]

Good catch. Done.

+  arc::ArcServiceManager::Get()->RemoveObserver(this);
+}
+
 void EventRouter::OnIntentFiltersUpdated() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   BroadcastEvent(profile_,
@@ -412,9 +417,6 @@ void EventRouter::OnIntentFiltersUpdated() {
 void EventRouter::Shutdown() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  if (arc::ArcServiceManager::IsInitialized())
-    arc::ArcServiceManager::Get()->RemoveObserver(this);
-
   chromeos::system::TimezoneSettings::GetInstance()->RemoveObserver(this);
 
   DLOG_IF(WARNING, !file_watchers_.empty())