Assume all providers may give zero suggest responses.

chrome/browser/autocomplete/bookmark_provider.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/autocomplete/bookmark_provider.h"
 
 #include <algorithm>
 #include <functional>
 #include <vector>
 
@@ skipping 47 matching lines @@
     : AutocompleteProvider(AutocompleteProvider::TYPE_BOOKMARK),
       profile_(profile),
       bookmark_model_(NULL) {
   if (profile) {
     bookmark_model_ = BookmarkModelFactory::GetForProfile(profile);
     languages_ = profile_->GetPrefs()->GetString(prefs::kAcceptLanguages);
   }
 }
 
 void BookmarkProvider::Start(const AutocompleteInput& input,
-                             bool minimal_changes) {
-  if (minimal_changes)
+                             bool minimal_changes,
+                             bool on_focus) {
+  if (minimal_changes || on_focus)

[Peter Kasting, 2015/01/07 20:16:36]

This isn't equivalent to the previous behavior, which would have cleared
|matches_| before returning.

[Maria, 2015/01/08 07:52:38]

Done.

     return;
   matches_.clear();
 
   if (input.text().empty() ||
       (input.type() == metrics::OmniboxInputType::FORCED_QUERY))
     return;
 
   DoAutocomplete(input);
 }
 
@@ skipping 257 matching lines @@
        i != positions.end();
        ++i) {
     AutocompleteMatch::ACMatchClassifications new_class;
     AutocompleteMatch::ClassifyLocationInString(i->first, i->second - i->first,
         text_length, url_style, &new_class);
     classifications = AutocompleteMatch::MergeClassifications(
         classifications, new_class);
   }
   return classifications;
 }