Assume all providers may give zero suggest responses.

chrome/browser/autocomplete/autocomplete_provider_unittest.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 "components/omnibox/autocomplete_provider.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 39 matching lines @@
                Profile* profile,
                const base::string16 match_keyword)
       : AutocompleteProvider(AutocompleteProvider::TYPE_SEARCH),
         listener_(NULL),
         profile_(profile),
         relevance_(relevance),
         prefix_(prefix),
         match_keyword_(match_keyword) {
   }
 
-  void Start(const AutocompleteInput& input, bool minimal_changes) override;
+  void Start(const AutocompleteInput& input,
+             bool minimal_changes,
+             bool called_due_to_focus) override;
 
   void set_listener(AutocompleteProviderListener* listener) {
     listener_ = listener;
   }
 
  private:
   ~TestProvider() override {}
 
   void Run();
 
   void AddResults(int start_at, int num);
   void AddResultsWithSearchTermsArgs(
       int start_at,
       int num,
       AutocompleteMatch::Type type,
       const TemplateURLRef::SearchTermsArgs& search_terms_args);
 
   AutocompleteProviderListener* listener_;
   Profile* profile_;
   int relevance_;
   const base::string16 prefix_;
   const base::string16 match_keyword_;
 };
 
 void TestProvider::Start(const AutocompleteInput& input,
-                         bool minimal_changes) {
+                         bool minimal_changes,
+                         bool called_due_to_focus) {
   if (minimal_changes)
     return;
 
   matches_.clear();
 
+  if (called_due_to_focus)
+    return;
+
   // Generate 4 results synchronously, the rest later.
   AddResults(0, 1);
   AddResultsWithSearchTermsArgs(
       1, 1, AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED,
       TemplateURLRef::SearchTermsArgs(base::ASCIIToUTF16("echo")));
   AddResultsWithSearchTermsArgs(
       2, 1, AutocompleteMatchType::NAVSUGGEST,
       TemplateURLRef::SearchTermsArgs(base::ASCIIToUTF16("nav")));
   AddResultsWithSearchTermsArgs(
       3, 1, AutocompleteMatchType::SEARCH_SUGGEST,
@@ skipping 625 matching lines @@
   url = GetDestinationURL(match, base::TimeDelta::FromMilliseconds(2456));
   EXPECT_EQ("//aqs=chrome.0.69i57j69i58j5l2j0l3j69i59.2456j0j4&", url.path());
 
   // Test page classification and field trial triggered set.
   controller_->search_provider_->field_trial_triggered_in_session_ = true;
   EXPECT_TRUE(
       controller_->search_provider_->field_trial_triggered_in_session());
   url = GetDestinationURL(match, base::TimeDelta::FromMilliseconds(2456));
   EXPECT_EQ("//aqs=chrome.0.69i57j69i58j5l2j0l3j69i59.2456j1j4&", url.path());
 }