bookmarks: Fix mistakes found by cppcheck.

chrome/browser/bookmarks/bookmark_index_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 <string>
 #include <vector>
 
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/string_split.h"
@@ skipping 33 matching lines @@
   void ExpectMatches(const std::string& query,
                      const char** expected_titles,
                      size_t expected_count) {
     std::vector<std::string> title_vector;
     for (size_t i = 0; i < expected_count; ++i)
       title_vector.push_back(expected_titles[i]);
     ExpectMatches(query, title_vector);
   }
 
   void ExpectMatches(const std::string& query,
-                     const std::vector<std::string> expected_titles) {
+                     const std::vector<std::string>& expected_titles) {
     std::vector<bookmark_utils::TitleMatch> matches;
     model_->GetBookmarksWithTitlesMatching(ASCIIToUTF16(query), 1000, &matches);
     ASSERT_EQ(expected_titles.size(), matches.size());
     for (size_t i = 0; i < expected_titles.size(); ++i) {
       bool found = false;
       for (size_t j = 0; j < matches.size(); ++j) {
         if (ASCIIToUTF16(expected_titles[i]) == matches[j].node->GetTitle()) {
           matches.erase(matches.begin() + j);
           found = true;
           break;
@@ skipping 231 matching lines @@
   EXPECT_EQ(data[1].url, matches[3].node->url());
 
   matches.clear();
   // Select top two matches.
   model->GetBookmarksWithTitlesMatching(ASCIIToUTF16("google"), 2, &matches);
 
   EXPECT_EQ(2, static_cast<int>(matches.size()));
   EXPECT_EQ(data[0].url, matches[0].node->url());
   EXPECT_EQ(data[3].url, matches[1].node->url());
 }