TemplateURLService: notify observers of shutdown

components/search_engines/template_url_service.cc

Index: components/search_engines/template_url_service.cc
diff --git a/components/search_engines/template_url_service.cc b/components/search_engines/template_url_service.cc
index ca6401082f4f5c12ba4f65d6e200f92f2f448f07..ab0ba5766fbc705618980ded02603c0ab076ef00 100644
--- a/components/search_engines/template_url_service.cc
+++ b/components/search_engines/template_url_service.cc
@@ -872,6 +872,9 @@ void TemplateURLService::OnHistoryURLVisited(const URLVisitedDetails& details) {
 }
 
 void TemplateURLService::Shutdown() {
+  for (auto& observer : model_observers_)
+    observer.OnTemplateURLServiceShuttingDown();
+
   if (client_)
     client_->Shutdown();
   // This check has to be done at Shutdown() instead of in the dtor to ensure