[NTP Snippets] Clear the snippets when the user signs out

components/ntp_snippets/ntp_snippets_service.cc

Index: components/ntp_snippets/ntp_snippets_service.cc
diff --git a/components/ntp_snippets/ntp_snippets_service.cc b/components/ntp_snippets/ntp_snippets_service.cc
index 02524508ceca77bf9620436e54bc6604c47ab25e..555e101213efd53b78add33ac071a137b1e92755 100644
--- a/components/ntp_snippets/ntp_snippets_service.cc
+++ b/components/ntp_snippets/ntp_snippets_service.cc
@@ -331,6 +331,11 @@ void NTPSnippetsService::OnSuggestionsChanged(
   StoreSnippetsToPrefs();
   StoreSnippetHostsToPrefs(hosts);
 
+  if (hosts.empty()) {
+    FOR_EACH_OBSERVER(NTPSnippetsServiceObserver, observers_,
+                      NTPSnippetsServiceCleared());
+  }
+
   FOR_EACH_OBSERVER(NTPSnippetsServiceObserver, observers_,
                     NTPSnippetsServiceLoaded());