Loading the Launcher with a Locked Profile launched UserManager.

chrome/browser/ui/app_list/app_list_service_impl.cc

Index: chrome/browser/ui/app_list/app_list_service_impl.cc
diff --git a/chrome/browser/ui/app_list/app_list_service_impl.cc b/chrome/browser/ui/app_list/app_list_service_impl.cc
index 8b5c91422bc3020ad6c4d5bd64f7bb065c7ddcbf..3808fee61706a952be5251d787ac969d2737f888 100644
--- a/chrome/browser/ui/app_list/app_list_service_impl.cc
+++ b/chrome/browser/ui/app_list/app_list_service_impl.cc
@@ -123,6 +123,7 @@ class ProfileStoreImpl : public ProfileStore {
   }
 
   Profile* GetProfileByPath(const base::FilePath& path) override {
+    DCHECK(!IsProfileLocked(path));
     return profile_manager_->GetProfileByPath(path);
   }
 
@@ -138,6 +139,14 @@ class ProfileStoreImpl : public ProfileStore {
         profile_info.ProfileIsSupervisedAtIndex(profile_index);
   }
 
+  bool IsProfileLocked(const base::FilePath& profile_path) override {
+    ProfileInfoCache& profile_info =
+        g_browser_process->profile_manager()->GetProfileInfoCache();
+    size_t profile_index = profile_info.GetIndexOfProfileWithPath(profile_path);
+    return profile_index != std::string::npos &&
+        profile_info.ProfileIsSigninRequiredAtIndex(profile_index);
+  }
+
  private:
   ProfileManager* profile_manager_;
   base::WeakPtrFactory<ProfileStoreImpl> weak_factory_;