Assume all providers may give zero suggest responses.

chrome/browser/autocomplete/history_quick_provider.h

Index: chrome/browser/autocomplete/history_quick_provider.h
diff --git a/chrome/browser/autocomplete/history_quick_provider.h b/chrome/browser/autocomplete/history_quick_provider.h
index fbd93f4e4e9aba5a17ba83f2ff8ddb4d9f2e952e..09980e8eb02f086a2c34d4e0c335f22abd62b2a5 100644
--- a/chrome/browser/autocomplete/history_quick_provider.h
+++ b/chrome/browser/autocomplete/history_quick_provider.h
@@ -31,7 +31,9 @@ class HistoryQuickProvider : public HistoryProvider {
 
   // AutocompleteProvider. |minimal_changes| is ignored since there is no asynch
   // completion performed.
-  void Start(const AutocompleteInput& input, bool minimal_changes) override;
+  void Start(const AutocompleteInput& input,
+             bool minimal_changes,
+             bool on_focus) override;
 
   // Disable this provider. For unit testing purposes only. This is required
   // because this provider is closely associated with the HistoryURLProvider