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

chrome/browser/nacl_host/test/gdb_debug_stub_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/path_service.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/process/process.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/test/ppapi/ppapi_test.h"
 #include "components/nacl/browser/nacl_browser.h"
 #include "components/nacl/common/nacl_switches.h"
 #include "content/public/test/test_utils.h"
 
 class NaClGdbDebugStubTest : public PPAPINaClNewlibTest {
  public:
   NaClGdbDebugStubTest() {
   }
 
   void SetUpCommandLine(base::CommandLine* command_line) override;
 
   void StartTestScript(base::Process* test_process,
-                       std::string test_name, int debug_stub_port);
+                       const std::string& test_name,
+                       int debug_stub_port);
   void RunDebugStubTest(const std::string& nacl_module,
                         const std::string& test_name);
 };
 
 void NaClGdbDebugStubTest::SetUpCommandLine(base::CommandLine* command_line) {
   PPAPINaClNewlibTest::SetUpCommandLine(command_line);
   command_line->AppendSwitch(switches::kEnableNaClDebug);
 }
 
 void NaClGdbDebugStubTest::StartTestScript(base::Process* test_process,
-                                           std::string test_name,
+                                           const std::string& test_name,
                                            int debug_stub_port) {
   // We call python script to reuse GDB RSP protocol implementation.
   base::CommandLine cmd(base::FilePath(FILE_PATH_LITERAL("python")));
   base::FilePath script;
   PathService::Get(chrome::DIR_TEST_DATA, &script);
   script = script.AppendASCII("nacl/debug_stub_browser_tests.py");
   cmd.AppendArgPath(script);
   cmd.AppendArg(base::IntToString(debug_stub_port));
   cmd.AppendArg(test_name);
   LOG(INFO) << cmd.GetCommandLineString();
@@ skipping 33 matching lines @@
 #elif defined(OS_LINUX) && !defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
 // Timing out on ARM linux: http://crbug.com/238469
 # define MAYBE_Breakpoint DISABLED_Breakpoint
 #else
 # define MAYBE_Breakpoint Breakpoint
 #endif
 
 IN_PROC_BROWSER_TEST_F(NaClGdbDebugStubTest, MAYBE_Breakpoint) {
   RunDebugStubTest("Empty", "breakpoint");
 }