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

chrome/browser/extensions/extension_startup_browsertest.cc

 // Copyright (c) 2008 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 <vector>
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
@@ skipping 42 matching lines @@
       src_dir = src_dir.AppendASCII("extensions").AppendASCII("good");
 
       file_util::CopyFile(src_dir.AppendASCII("Preferences"),
                           preferences_file_);
       file_util::CopyDirectory(src_dir.AppendASCII("Extensions"),
                                profile_dir, true);  // recursive
     } else {
       command_line->AppendSwitch(switches::kDisableExtensions);
     }
 
-    if (!load_extension_.value().empty()) {
-      command_line->AppendSwitchWithValue(switches::kLoadExtension,
-                                          load_extension_.ToWStringHack());
+    if (!load_extension_.empty()) {
+      command_line->AppendSwitchPath(switches::kLoadExtension, load_extension_);
       command_line->AppendSwitch(switches::kDisableExtensionsFileAccessCheck);
     }
   }
 
   virtual void TearDown() {
     EXPECT_TRUE(file_util::Delete(preferences_file_, false));
 
     // TODO(phajdan.jr): Check return values of the functions below, carefully.
     file_util::Delete(user_scripts_dir_, true);
     file_util::Delete(extensions_dir_, true);
@@ skipping 111 matching lines @@
 // Flaky (times out) on Mac/Windows. http://crbug.com/46301.
 #if defined(OS_MACOSX) || defined(OS_WIN)
 #define MAYBE_Test FLAKY_Test
 #else
 #define MAYBE_Test Test
 #endif
 IN_PROC_BROWSER_TEST_F(ExtensionsLoadTest, MAYBE_Test) {
   WaitForServicesToStart(1, false);
   TestInjection(true, true);
 }