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

chrome/browser/browser_main.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 "chrome/browser/browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 554 matching lines @@
     // SkBitmaps from the ResourceBundle.
     ResourceBundle::CleanupSharedInstance();
   }
 
   if (!new_user_data_dir.empty()) {
     // Because of the way CommandLine parses, it's sufficient to append a new
     // --user-data-dir switch.  The last flag of the same name wins.
     // TODO(tc): It would be nice to remove the flag we don't want, but that
     // sounds risky if we parse differently than CommandLineToArgvW.
     CommandLine new_command_line = parameters.command_line_;
-    new_command_line.AppendSwitchWithValue(switches::kUserDataDir,
-                                           new_user_data_dir.ToWStringHack());
+    new_command_line.AppendSwitchPath(switches::kUserDataDir,
+                                      new_user_data_dir);
     base::LaunchApp(new_command_line, false, false, NULL);
   }
 #else
   // TODO(port): fix this.  See comments near the definition of
   // user_data_dir.  It is better to CHECK-fail here than it is to
   // silently exit because of missing code in the above test.
   CHECK(profile) << "Cannot get default profile.";
 #endif
 
   return NULL;
@@ skipping 678 matching lines @@
 
   metrics->Stop();
 
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process.release());
   browser_shutdown::Shutdown();
 
   return result_code;
 }