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

ppapi/tests/test_file_ref.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 "ppapi/tests/test_file_ref.h"
 
 #include <stdio.h>
 #include <vector>
 
 #include "ppapi/c/pp_errors.h"
@@ skipping 67 matching lines @@
   RUN_TEST_FORCEASYNC_AND_NOT(QueryAndTouchFile, filter);
   RUN_TEST_FORCEASYNC_AND_NOT(DeleteFileAndDirectory, filter);
   RUN_TEST_FORCEASYNC_AND_NOT(RenameFileAndDirectory, filter);
   RUN_CALLBACK_TEST(TestFileRef, Query, filter);
   RUN_TEST_FORCEASYNC_AND_NOT(FileNameEscaping, filter);
 }
 
 std::string TestFileRef::TestCreate() {
   std::vector<std::string> invalid_paths;
   invalid_paths.push_back("invalid_path");  // no '/' at the first character
-  invalid_paths.push_back("");  // empty path
+  invalid_paths.push_back(std::string());   // empty path
   // The following are directory traversal checks
   invalid_paths.push_back("..");
   invalid_paths.push_back("/../invalid_path");
   invalid_paths.push_back("/../../invalid_path");
   invalid_paths.push_back("/invalid/../../path");
   const size_t num_invalid_paths = invalid_paths.size();
 
   pp::FileSystem file_system_pers(
       instance_, PP_FILESYSTEMTYPE_LOCALPERSISTENT);
   pp::FileSystem file_system_temp(
@@ skipping 692 matching lines @@
     if (entries.empty())
       return "Entry was not found.";
     if (entries.size() != 1)
       return "Directory had too many entries.";
     if (entries.front().file_ref().GetName().AsString() != kTerribleName)
       return "Entry name did not match.";
   }
 
   PASS();
 }