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

chrome/test/perf/url_fetch_test.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 "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 59 matching lines @@
           UTF8ToWide(wait_js_frame_xpath),
           UTF8ToWide(wait_js_expr),
           wait_js_timeout);
       ASSERT_TRUE(completed);
     }
     if (var_to_fetch) {
       std::string script = base::StringPrintf(
           "window.domAutomationController.send(%s);", var_to_fetch);
 
       std::wstring value;
-      bool success = tab->ExecuteAndExtractString(L"", ASCIIToWide(script),
-                                                  &value);
+      bool success = tab->ExecuteAndExtractString(
+          std::wstring(), ASCIIToWide(script), &value);
       ASSERT_TRUE(success);
       result->javascript_variable = WideToUTF8(value);
     }
   }
 };
 
 bool WriteValueToFile(std::string value, const base::FilePath& path) {
   int retval = file_util::WriteFile(path, value.c_str(), value.length());
   return retval == static_cast<int>(value.length());
 }
@@ skipping 83 matching lines @@
   // Write out the JS Variable if requested
   base::FilePath jsvar_output_path =
       cmd_line->GetSwitchValuePath("jsvar_output");
   if (!jsvar_output_path.value().empty()) {
     ASSERT_TRUE(WriteValueToFile(result.javascript_variable,
                                  jsvar_output_path));
   }
 }
 
 }  // namespace