chromeos: Avoid bogus child account warning at startup.

chrome/browser/supervised_user/child_accounts/child_account_service.cc

Index: chrome/browser/supervised_user/child_accounts/child_account_service.cc
diff --git a/chrome/browser/supervised_user/child_accounts/child_account_service.cc b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
index 5081a2d60d4669e1f3d6d689c3f357b6b1a024e5..750a47c6109fef7a358937c78a7838cc6fffbac7 100644
--- a/chrome/browser/supervised_user/child_accounts/child_account_service.cc
+++ b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
@@ -298,9 +298,9 @@ void ChildAccountService::PropagateChildStatusToUser(bool is_child) {
       chromeos::ProfileHelper::Get()->GetUserByProfile(profile_);
   if (user) {
     user_manager::UserManager::Get()->ChangeUserChildStatus(user, is_child);
-  } else {
-    LOG(WARNING) <<
-        "User instance wasn't found while setting child account flag.";
+  } else if (!chromeos::ProfileHelper::Get()->IsSigninProfile(profile_)) {
+    LOG(WARNING)

[Bernhard Bauer, 2016/08/10 14:23:57]

Actually, would it make sense to have a DCHECK/CHECK here? Could this
legitimately happen outside of the signin profile?

[Daniel Erat, 2016/08/10 15:08:40]

sorry, i have no idea -- i've never looked at this code before yesterday.

re switching it to a check, is it a situation that means that we should expect
undefined behavior or security issues? is it likely that restarting chrome will
clear it up? if not, i don't think a check is appropriate.

[Bernhard Bauer, 2016/08/10 17:17:29]

Hm, I'm thinking this is a situation that is _supposed_ to never happen (at
least I don't know when it would legitimately happen), so a DCHECK would be
appropriate (cf.
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md...).

[Daniel Erat, 2016/08/10 20:12:12]

how about LOG(DFATAL)? then we get a crash in debug builds as if we used
DCHECK() and an error message in release builds.

+        << "User instance wasn't found while setting child account flag.";
   }
 #endif
 }