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

device/bluetooth/bluetooth_utils.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 "device/bluetooth/bluetooth_utils.h"
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 
 namespace {
 static const char* kCommonUuidPostfix = "-0000-1000-8000-00805f9b34fb";
 static const char* kCommonUuidPrefix = "0000";
 static const int kUuidSize = 36;
 }  // namespace
 
 namespace device {
 namespace bluetooth_utils {
 
 std::string CanonicalUuid(std::string uuid) {
   if (uuid.empty())
-    return "";
+    return std::string();
 
   if (uuid.size() < 11 && uuid.find("0x") == 0)
     uuid = uuid.substr(2);
 
   if (!(uuid.size() == 4 || uuid.size() == 8 || uuid.size() == 36))
-    return "";
+    return std::string();
 
   if (uuid.size() == 4 || uuid.size() == 8) {
     for (size_t i = 0; i < uuid.size(); ++i) {
       if (!IsHexDigit(uuid[i]))
-        return "";
+        return std::string();
     }
 
     if (uuid.size() == 4)
       return kCommonUuidPrefix + uuid + kCommonUuidPostfix;
 
     return uuid + kCommonUuidPostfix;
   }
 
   std::string uuid_result(uuid);
   for (int i = 0; i < kUuidSize; ++i) {
     if (i == 8 || i == 13 || i == 18 || i == 23) {
       if (uuid[i] != '-')
-        return "";
+        return std::string();
     } else {
       if (!IsHexDigit(uuid[i]))
-        return "";
+        return std::string();
       uuid_result[i] = tolower(uuid[i]);
     }
   }
   return uuid_result;
 }
 
 }  // namespace bluetooth_utils
 }  // namespace device