Assume all providers may give zero suggest responses.

chrome/browser/autocomplete/bookmark_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 "chrome/browser/autocomplete/bookmark_provider.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 249 matching lines @@
     // This ensures that empty titles yield empty classifications.
     {"emptytitle",            1, {}},
   };
 
   for (size_t i = 0; i < arraysize(query_data); ++i) {
     AutocompleteInput input(base::ASCIIToUTF16(query_data[i].query),
                             base::string16::npos, std::string(), GURL(),
                             metrics::OmniboxEventProto::INVALID_SPEC, false,
                             false, false, true,
                             ChromeAutocompleteSchemeClassifier(profile_.get()));
-    provider_->Start(input, false);
+    provider_->Start(input, false, false);
     const ACMatches& matches(provider_->matches());
     // Validate number of results is as expected.
     EXPECT_LE(matches.size(), query_data[i].match_count)
         << "One or more of the following matches were unexpected:\n"
         << MatchesAsString16(matches)
         << "For query '" << query_data[i].query << "'.";
     EXPECT_GE(matches.size(), query_data[i].match_count)
         << "One or more expected matches are missing. Matches found:\n"
         << MatchesAsString16(matches)
         << "for query '" << query_data[i].query << "'.";
@@ skipping 60 matching lines @@
                       "worming burns #10",   // boosted but longer title
                       "burning worms #2"}},  // not boosted
   };
 
   for (size_t i = 0; i < arraysize(query_data); ++i) {
     AutocompleteInput input(base::ASCIIToUTF16(query_data[i].query),
                             base::string16::npos, std::string(), GURL(),
                             metrics::OmniboxEventProto::INVALID_SPEC, false,
                             false, false, true,
                             ChromeAutocompleteSchemeClassifier(profile_.get()));
-    provider_->Start(input, false);
+    provider_->Start(input, false, false);
     const ACMatches& matches(provider_->matches());
     // Validate number and content of results is as expected.
     for (size_t j = 0; j < std::max(query_data[i].match_count, matches.size());
          ++j) {
       EXPECT_LT(j, query_data[i].match_count) << "    Unexpected match '"
           << base::UTF16ToUTF8(matches[j].description) << "' for query: '"
           <<  query_data[i].query << "'.";
       if (j >= query_data[i].match_count)
         continue;
       EXPECT_LT(j, matches.size()) << "    Missing match '"
@@ skipping 79 matching lines @@
     { "versi",     "chrome://version",           "0:1,9:3,14:1"          }
   };
 
   for (size_t i = 0; i < arraysize(query_data); ++i) {
     std::string description = "for query=" + query_data[i].query;
     AutocompleteInput input(base::ASCIIToUTF16(query_data[i].query),
                             base::string16::npos, std::string(), GURL(),
                             metrics::OmniboxEventProto::INVALID_SPEC, false,
                             false, false, true,
                             ChromeAutocompleteSchemeClassifier(profile_.get()));
-    provider_->Start(input, false);
+    provider_->Start(input, false, false);
     const ACMatches& matches(provider_->matches());
     ASSERT_EQ(1U, matches.size()) << description;
     const AutocompleteMatch& match = matches[0];
     EXPECT_EQ(base::ASCIIToUTF16(query_data[i].expected_contents),
               match.contents) << description;
     std::vector<std::string> class_strings;
     base::SplitString(
         query_data[i].expected_contents_class, ',', &class_strings);
     ASSERT_EQ(class_strings.size(), match.contents_class.size())
         << description;
     for (size_t i = 0; i < class_strings.size(); ++i) {
       std::vector<std::string> chunks;
       base::SplitString(class_strings[i], ':', &chunks);
       ASSERT_EQ(2U, chunks.size()) << description;
       size_t offset;
       EXPECT_TRUE(base::StringToSizeT(chunks[0], &offset)) << description;
       EXPECT_EQ(offset, match.contents_class[i].offset) << description;
       int style;
       EXPECT_TRUE(base::StringToInt(chunks[1], &style)) << description;
       EXPECT_EQ(style, match.contents_class[i].style) << description;
     }
   }
 }
+
+TEST_F(BookmarkProviderTest, DoesNotProvideMatchesOnFocus) {
+  AutocompleteInput input(base::ASCIIToUTF16("foo"),
+                          base::string16::npos, std::string(), GURL(),
+                          metrics::OmniboxEventProto::INVALID_SPEC, false,
+                          false, false, true,
+                          ChromeAutocompleteSchemeClassifier(profile_.get()));
+  provider_->Start(input, false, true);
+  EXPECT_TRUE(provider_->matches().empty());
+}