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

net/http/http_auth_handler_digest.cc

 // Copyright (c) 2011 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/http/http_auth_handler_digest.h"
 
 #include <string>
 
 #include "base/i18n/icu_string_conversions.h"
 #include "base/logging.h"
@@ skipping 252 matching lines @@
     DVLOG(1) << "Skipping unrecognized digest property";
     // TODO(eroman): perhaps we should fail instead of silently skipping?
   }
   return true;
 }
 
 // static
 std::string HttpAuthHandlerDigest::QopToString(QualityOfProtection qop) {
   switch (qop) {
     case QOP_UNSPECIFIED:
-      return "";
+      return std::string();
     case QOP_AUTH:
       return "auth";
     default:
       NOTREACHED();
-      return "";
+      return std::string();
   }
 }
 
 // static
 std::string HttpAuthHandlerDigest::AlgorithmToString(
     DigestAlgorithm algorithm) {
   switch (algorithm) {
     case ALGORITHM_UNSPECIFIED:
-      return "";
+      return std::string();
     case ALGORITHM_MD5:
       return "MD5";
     case ALGORITHM_MD5_SESS:
       return "MD5-sess";
     default:
       NOTREACHED();
-      return "";
+      return std::string();
   }
 }
 
 void HttpAuthHandlerDigest::GetRequestMethodAndPath(
     const HttpRequestInfo* request,
     std::string* method,
     std::string* path) const {
   DCHECK(request);
 
   const GURL& url = request->url;
@@ skipping 67 matching lines @@
     // TODO(eroman): Supposedly IIS server requires quotes surrounding qop.
     authorization += ", qop=" + QopToString(qop_);
     authorization += ", nc=" + nc;
     authorization += ", cnonce=" + HttpUtil::Quote(cnonce);
   }
 
   return authorization;
 }
 
 }  // namespace net