Cleanup: Pass std::string as const reference if possible

chrome/browser/nacl_host/test/nacl_gdb_browsertest.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/environment.h"
 #include "base/files/file_util.h"
 #include "base/path_service.h"
 #include "base/win/windows_version.h"
 #include "chrome/common/chrome_switches.h"
@@ skipping 16 matching lines @@
     PPAPINaClNewlibTest::SetUpCommandLine(command_line);
 
     base::FilePath mock_nacl_gdb;
     EXPECT_TRUE(PathService::Get(base::DIR_EXE, &mock_nacl_gdb));
     mock_nacl_gdb = mock_nacl_gdb.Append(kMockNaClGdb);
     command_line->AppendSwitchPath(switches::kNaClGdb, mock_nacl_gdb);
     EXPECT_TRUE(base::CreateTemporaryFile(&script_));
     command_line->AppendSwitchPath(switches::kNaClGdbScript, script_);
   }
 
-  void RunWithNaClGdb(std::string test_name) {
+  void RunWithNaClGdb(const std::string& test_name) {
     base::FilePath mock_nacl_gdb_file;
     scoped_ptr<base::Environment> env(base::Environment::Create());
     std::string content;
     // TODO(halyavin): Make this test work on Windows 32-bit. Currently this
     // is not possible because NaCl doesn't work without sandbox since 1Gb of
     // space is not reserved. We can't reserve 1Gb of space because
     // base::LaunchProcess doesn't support creating suspended processes. We need
     // to either add suspended process support to base::LaunchProcess or use
     // Win API.
 #if defined(OS_WIN)
@@ skipping 23 matching lines @@
 
 // Fails on the ASAN test bot. See http://crbug.com/122219
 #if defined(ADDRESS_SANITIZER)
 #define MAYBE_Empty DISABLED_Empty
 #else
 #define MAYBE_Empty Empty
 #endif
 IN_PROC_BROWSER_TEST_F(NaClGdbTest, MAYBE_Empty) {
   RunWithNaClGdb("Empty");
 }