Assume all providers may give zero suggest responses.

chrome/browser/autocomplete/history_quick_provider.cc

Index: chrome/browser/autocomplete/history_quick_provider.cc
diff --git a/chrome/browser/autocomplete/history_quick_provider.cc b/chrome/browser/autocomplete/history_quick_provider.cc
index de1c711188fcf3f82c8af254f8e4c2e6d6a57d67..8f3d78efd97c789161b0052f9af7765fe682262e 100644
--- a/chrome/browser/autocomplete/history_quick_provider.cc
+++ b/chrome/browser/autocomplete/history_quick_provider.cc
@@ -56,9 +56,10 @@ HistoryQuickProvider::HistoryQuickProvider(Profile* profile)
 }
 
 void HistoryQuickProvider::Start(const AutocompleteInput& input,
-                                 bool minimal_changes) {
+                                 bool minimal_changes,
+                                 bool on_focus) {
   matches_.clear();
-  if (disabled_)
+  if (disabled_ || on_focus)
     return;
 
   // Don't bother with INVALID and FORCED_QUERY.