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

net/base/mime_util.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 <algorithm>
 #include <iterator>
 #include <map>
 #include <string>
 
 #include "net/base/mime_util.h"
@@ skipping 949 matching lines @@
     codecs->push_back(proprietary_media_codecs[i]);
 #endif
 }
 
 const std::string GetIANAMediaType(const std::string& mime_type) {
   for (size_t i = 0; i < arraysize(kIanaMediaTypes); ++i) {
     if (StartsWithASCII(mime_type, kIanaMediaTypes[i].matcher, true)) {
       return kIanaMediaTypes[i].name;
     }
   }
-  return "";
+  return std::string();
 }
 
 CertificateMimeType GetCertificateMimeTypeForMimeType(
     const std::string& mime_type) {
   // Don't create a map, there is only one entry in the table,
   // except on Android.
   for (size_t i = 0; i < arraysize(supported_certificate_types); ++i) {
     if (mime_type == net::supported_certificate_types[i].mime_type)
       return net::supported_certificate_types[i].cert_type;
   }
   return CERTIFICATE_MIME_TYPE_UNKNOWN;
 }
 
 bool IsSupportedCertificateMimeType(const std::string& mime_type) {
   CertificateMimeType file_type =
       GetCertificateMimeTypeForMimeType(mime_type);
   return file_type != CERTIFICATE_MIME_TYPE_UNKNOWN;
 }
 
 }  // namespace net