Rewrite std::string("") to std::string(), Linux edition.

extensions/common/matcher/url_matcher.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 "extensions/common/matcher/url_matcher.h"
 
 #include <algorithm>
 #include <iterator>
 
 #include "base/logging.h"
@@ skipping 238 matching lines @@
 URLMatcherConditionFactory::URLMatcherConditionFactory() : id_counter_(0) {}
 
 URLMatcherConditionFactory::~URLMatcherConditionFactory() {
   STLDeleteElements(&substring_pattern_singletons_);
   STLDeleteElements(&regex_pattern_singletons_);
 }
 
 std::string URLMatcherConditionFactory::CanonicalizeURLForComponentSearches(
     const GURL& url) const {
   return kBeginningOfURL + CanonicalizeHostname(url.host()) + kEndOfDomain +
-      url.path() + kEndOfPath + (url.has_query() ? "?" + url.query() : "") +
-      kEndOfURL;
+         url.path() + kEndOfPath +
+         (url.has_query() ? "?" + url.query() : std::string()) + kEndOfURL;
 }
 
 URLMatcherCondition URLMatcherConditionFactory::CreateHostPrefixCondition(
     const std::string& prefix) {
   return CreateCondition(URLMatcherCondition::HOST_PREFIX,
       kBeginningOfURL + CanonicalizeHostname(prefix));
 }
 
 URLMatcherCondition URLMatcherConditionFactory::CreateHostSuffixCondition(
     const std::string& suffix) {
@@ skipping 541 matching lines @@
 
 void URLMatcher::UpdateInternalDatastructures() {
   UpdateSubstringSetMatcher(false);
   UpdateSubstringSetMatcher(true);
   UpdateRegexSetMatcher();
   UpdateTriggers();
   UpdateConditionFactory();
 }
 
 }  // namespace extensions