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

net/proxy/dhcp_proxy_script_fetcher.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 "net/proxy/dhcp_proxy_script_fetcher.h"
 
 #include "net/base/net_errors.h"
 
 namespace net {
 
 std::string DhcpProxyScriptFetcher::GetFetcherName() const {
-  return "";
+  return std::string();
 }
 
 DhcpProxyScriptFetcher::DhcpProxyScriptFetcher() {}
 
 DhcpProxyScriptFetcher::~DhcpProxyScriptFetcher() {}
 
 DoNothingDhcpProxyScriptFetcher::DoNothingDhcpProxyScriptFetcher() {}
 
 DoNothingDhcpProxyScriptFetcher::~DoNothingDhcpProxyScriptFetcher() {}
 
 int DoNothingDhcpProxyScriptFetcher::Fetch(
     base::string16* utf16_text, const CompletionCallback& callback) {
   return ERR_NOT_IMPLEMENTED;
 }
 
 void DoNothingDhcpProxyScriptFetcher::Cancel() {}
 
 const GURL& DoNothingDhcpProxyScriptFetcher::GetPacURL() const {
   return gurl_;
 }
 
 }  // namespace net