Cleanup: Pass std::string as const reference if possible

components/url_matcher/url_matcher_unittest.cc

 // Copyright 2013 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/url_matcher/url_matcher.h"
 
 #include "base/strings/string_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
@@ skipping 129 matching lines @@
         << "Test " << i << " of test_equal failed";
   }
 }
 
 //
 // URLMatcherConditionFactory
 //
 
 namespace {
 
-bool Matches(const URLMatcherCondition& condition, std::string text) {
+bool Matches(const URLMatcherCondition& condition, const std::string& text) {
   return text.find(condition.string_pattern()->pattern()) !=
       std::string::npos;
 }
 
 }  // namespace
 
 TEST(URLMatcherConditionFactoryTest, GURLCharacterSet) {
   // GURL guarantees that neither domain, nor path, nor query may contain
   // non ASCII-7 characters. We test this here, because a change to this
   // guarantee breaks this implementation horribly.
@@ skipping 816 matching lines @@
   conditions.insert(factory->CreateOriginAndPathMatchesCondition("val"));
   const int kConditionSetId = 1;
   URLMatcherConditionSet::Vector insert;
   insert.push_back(make_scoped_refptr(
       new URLMatcherConditionSet(kConditionSetId, conditions)));
   matcher.AddConditionSets(insert);
   EXPECT_EQ(0u, matcher.MatchURL(url).size());
 }
 
 }  // namespace url_matcher