CommandLine: add a CopySwitchesFrom() for copying from another CommandLine

chrome/test/ui/ppapi_uitest.cc

 // Copyright (c) 2010 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/file_util.h"
 #include "base/path_service.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/automation/tab_proxy.h"
 #include "chrome/test/ui/ui_test.h"
@@ skipping 18 matching lines @@
  public:
   PPAPITest() {
     // Append the switch to register the pepper plugin.
     // library name = <out dir>/<test_name>.<library_extension>
     // MIME type = application/x-ppapi-<test_name>
     FilePath plugin_dir;
     PathService::Get(base::DIR_EXE, &plugin_dir);
 
     FilePath plugin_lib = plugin_dir.Append(library_name);
     EXPECT_TRUE(file_util::PathExists(plugin_lib));
-
-#if defined(OS_WIN)
-    std::wstring pepper_plugin = plugin_lib.value();
-#else
-    std::wstring pepper_plugin = UTF8ToWide(plugin_lib.value());
-#endif
-    pepper_plugin.append(L";application/x-ppapi-tests");
-    launch_arguments_.AppendSwitchWithValue(switches::kRegisterPepperPlugins,
-                                            pepper_plugin);
+    FilePath::StringType pepper_plugin = plugin_lib.value();
+    pepper_plugin.append(FILE_PATH_LITERAL(";application/x-ppapi-tests"));
+    launch_arguments_.AppendSwitchNative(switches::kRegisterPepperPlugins,
+                                         pepper_plugin);
 
     // The test sends us the result via a cookie.
     launch_arguments_.AppendSwitch(switches::kEnableFileCookies);
 
     // Some stuff is hung off of the testing interface which is not enabled
     // by default.
     launch_arguments_.AppendSwitch(switches::kEnablePepperTesting);
   }
 
   void RunTest(const std::string& test_case) {
@@ skipping 55 matching lines @@
 }
 
 #if defined(OS_LINUX)
 // Flaky, http://crbug.com/48544.
 TEST_F(PPAPITest, FLAKY_Scrollbar) {
 #else
 TEST_F(PPAPITest, Scrollbar) {
 #endif
   RunTest("Scrollbar");
 }