CommandLine: add a CopySwitchesFrom() and AppendSwitchPath()

These are two common patterns in Chrome code: copying a
subset of switches from one CommandLine to another, and
appending a FilePath to a CommandLine.  This sets me up
to do a lot more deprecation in a follow-up change.

Review URL: http://codereview.chromium.org/3012021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@54218 0039d316-1c4b-4281-b951-d872f2087c98

40 files changed, 165 insertions, 222 deletions

diff --git a/base/command_line.cc b/base/command_line.cc
index b11902b..19f508a 100644
--- a/base/command_line.cc
+++ b/base/command_line.cc
@@ -291,10 +291,10 @@ std::string CommandLine::GetSwitchValueASCII(
 
 FilePath CommandLine::GetSwitchValuePath(
     const std::string& switch_string) const {
-  return FilePath::FromWStringHack(GetSwitchValue(switch_string));
+  return FilePath(GetSwitchValueNative(switch_string));
 }
 
-std::wstring CommandLine::GetSwitchValue(
+CommandLine::StringType CommandLine::GetSwitchValueNative(
     const std::string& switch_string) const {
   std::string lowercased_switch(switch_string);
 #if defined(OS_WIN)
@@ -305,18 +305,26 @@ std::wstring CommandLine::GetSwitchValue(
       switches_.find(lowercased_switch);
 
   if (result == switches_.end()) {
-    return L"";
+    return CommandLine::StringType();
   } else {
-#if defined(OS_WIN)
     return result->second;
+  }
+}
+
+std::wstring CommandLine::GetSwitchValue(
+    const std::string& switch_string) const {
+  // TODO(evanm): deprecate.
+  CommandLine::StringType value = GetSwitchValueNative(switch_string);
+#if defined(OS_WIN)
+  return value;
 #else
-    return base::SysNativeMBToWide(result->second);
+  return base::SysNativeMBToWide(value);
 #endif
-  }
 }
 
 std::wstring CommandLine::GetSwitchValue(
     const std::wstring& switch_string) const {
+  // TODO(evanm): deprecate.
   return GetSwitchValue(WideToASCII(switch_string));
 }
 
@@ -377,6 +385,11 @@ void CommandLine::AppendSwitch(const std::string& switch_string) {
 
 void CommandLine::AppendSwitchWithValue(const std::string& switch_string,
                                         const std::wstring& value_string) {
+  AppendSwitchNative(switch_string, value_string);
+}
+
+void CommandLine::AppendSwitchNative(const std::string& switch_string,
+                                     const std::wstring& value_string) {
   std::wstring value_string_edit;
 
   // NOTE(jhughes): If the value contains a quotation mark at one
@@ -433,13 +446,18 @@ void CommandLine::AppendSwitch(const std::string& switch_string) {
   switches_[switch_string] = "";
 }
 
+void CommandLine::AppendSwitchNative(const std::string& switch_string,
+                                     const std::string& value) {
+  argv_.push_back(kSwitchPrefixes[0] + switch_string +
+                  kSwitchValueSeparator + value);
+  switches_[switch_string] = value;
+}
+
 void CommandLine::AppendSwitchWithValue(const std::string& switch_string,
                                         const std::wstring& value_string) {
+  // TODO(evanm): deprecate.
   std::string mb_value = base::SysWideToNativeMB(value_string);
-
-  argv_.push_back(kSwitchPrefixes[0] + switch_string +
-                  kSwitchValueSeparator + mb_value);
-  switches_[switch_string] = mb_value;
+  AppendSwitchNative(switch_string, mb_value);
 }
 
 void CommandLine::AppendLooseValue(const std::wstring& value) {
@@ -470,11 +488,27 @@ void CommandLine::PrependWrapper(const std::wstring& wrapper_wide) {
 
 #endif
 
+void CommandLine::AppendSwitchPath(const std::string& switch_string,
+                                   const FilePath& path) {
+  AppendSwitchNative(switch_string, path.value());
+}
+
 void CommandLine::AppendSwitchWithValue(const std::string& switch_string,
                                         const std::string& value_string) {
   AppendSwitchWithValue(switch_string, ASCIIToWide(value_string));
 }
 
+void CommandLine::CopySwitchesFrom(const CommandLine& source,
+                                   const char* const switches[],
+                                   size_t count) {
+  for (size_t i = 0; i < count; ++i) {
+    if (source.HasSwitch(switches[i])) {
+      StringType value = source.GetSwitchValueNative(switches[i]);
+      AppendSwitchNative(switches[i], value);
+    }
+  }
+}
+
 // private
 CommandLine::CommandLine() {
 }
diff --git a/base/command_line.h b/base/command_line.h
index 7ef83bc..89df392 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -101,10 +101,9 @@ class CommandLine {
   // Returns the value associated with the given switch.  If the
   // switch has no value or isn't present, this method returns
   // the empty string.
-  // TODO(evanm): move these into command_line.cpp once we've fixed the
-  // wstringness.
   std::string GetSwitchValueASCII(const std::string& switch_string) const;
   FilePath GetSwitchValuePath(const std::string& switch_string) const;
+  StringType GetSwitchValueNative(const std::string& switch_string) const;
 
   // Deprecated versions of the above.
   std::wstring GetSwitchValue(const std::string& switch_string) const;
@@ -156,12 +155,17 @@ class CommandLine {
                         const std::string& switch_string,
                         const std::wstring& value_string);
 
-  // Appends the given switch string (preceded by a space and a switch
-  // prefix) to the given string.
+  // Append a switch to the command line.
   void AppendSwitch(const std::string& switch_string);
 
-  // Appends the given switch string (preceded by a space and a switch
-  // prefix) to the given string, with the given value attached.
+  // Append a switch and value to the command line.
+  void AppendSwitchPath(const std::string& switch_string, const FilePath& path);
+  void AppendSwitchNative(const std::string& switch_string,
+                          const StringType& value);
+
+  // Append a switch and value to the command line.
+  // TODO(evanm): remove all AppendSwitchWithValue() instances.
+  // TODO(evanm): add an *ASCII() version.
   void AppendSwitchWithValue(const std::string& switch_string,
                              const std::wstring& value_string);
   void AppendSwitchWithValue(const std::string& switch_string,
@@ -179,6 +183,11 @@ class CommandLine {
   // "valgrind" or "gdb --args").
   void PrependWrapper(const std::wstring& wrapper);
 
+  // Copy a set of switches (and their values, if any) from another command
+  // line.  Commonly used when launching a subprocess.
+  void CopySwitchesFrom(const CommandLine& source, const char* const switches[],
+                        size_t count);
+
  private:
   friend class InProcessBrowserTest;
 
diff --git a/chrome/browser/browser_main.cc b/chrome/browser/browser_main.cc
index 2a2bc93..82bc172 100644
--- a/chrome/browser/browser_main.cc
+++ b/chrome/browser/browser_main.cc
@@ -572,8 +572,8 @@ Profile* CreateProfile(const MainFunctionParams& parameters,
     // 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
diff --git a/chrome/browser/browser_uitest.cc b/chrome/browser/browser_uitest.cc
index 404edd8..dce449d 100644
--- a/chrome/browser/browser_uitest.cc
+++ b/chrome/browser/browser_uitest.cc
@@ -278,8 +278,7 @@ public:
     file_util::Delete(tmp_profile_, true);
     file_util::CreateDirectory(tmp_profile_);
 
-    launch_arguments_.AppendSwitchWithValue(switches::kUserDataDir,
-                                            tmp_profile_.ToWStringHack());
+    launch_arguments_.AppendSwitchPath(switches::kUserDataDir, tmp_profile_);
   }
 
   bool LaunchAppWithProfile() {
diff --git a/chrome/browser/configuration_policy_pref_store_unittest.cc b/chrome/browser/configuration_policy_pref_store_unittest.cc
index 0762a6f..0cac13f 100644
--- a/chrome/browser/configuration_policy_pref_store_unittest.cc
+++ b/chrome/browser/configuration_policy_pref_store_unittest.cc
@@ -198,11 +198,11 @@ TEST_F(ConfigurationPolicyPrefStoreTest, TestSettingsProxyConfig) {
   command_line.AppendSwitch(switches::kNoProxyServer);
   command_line.AppendSwitch(switches::kProxyAutoDetect);
   command_line.AppendSwitchWithValue(switches::kProxyPacUrl,
-                                     L"http://chromium.org/test.pac");
+                                     "http://chromium.org/test.pac");
   command_line.AppendSwitchWithValue(switches::kProxyServer,
-                                     L"http://chromium2.org");
+                                     "http://chromium2.org");
   command_line.AppendSwitchWithValue(switches::kProxyBypassList,
-                                     L"http://chromium3.org");
+                                     "http://chromium3.org");
 
   ConfigurationPolicyPrefStore store(&command_line, NULL);
   EXPECT_EQ(store.ReadPrefs(), PrefStore::PREF_READ_ERROR_NONE);
@@ -232,11 +232,11 @@ TEST_F(ConfigurationPolicyPrefStoreTest, TestPolicyProxyConfigManualOverride) {
   command_line.AppendSwitch(switches::kNoProxyServer);
   command_line.AppendSwitch(switches::kProxyAutoDetect);
   command_line.AppendSwitchWithValue(switches::kProxyPacUrl,
-                                     L"http://chromium.org/test.pac");
+                                     "http://chromium.org/test.pac");
   command_line.AppendSwitchWithValue(switches::kProxyServer,
-                                     L"http://chromium.org");
+                                     "http://chromium.org");
   command_line.AppendSwitchWithValue(switches::kProxyBypassList,
-                                     L"http://chromium.org");
+                                     "http://chromium.org");
 
   scoped_ptr<MockConfigurationPolicyProvider> provider(
       new MockConfigurationPolicyProvider());
diff --git a/chrome/browser/extensions/extension_startup_browsertest.cc b/chrome/browser/extensions/extension_startup_browsertest.cc
index 0d056d0..165054d 100644
--- a/chrome/browser/extensions/extension_startup_browsertest.cc
+++ b/chrome/browser/extensions/extension_startup_browsertest.cc
@@ -60,9 +60,8 @@ class ExtensionStartupTestBase : public InProcessBrowserTest {
       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);
     }
   }
diff --git a/chrome/browser/extensions/extension_uitest.cc b/chrome/browser/extensions/extension_uitest.cc
index 8344d5d..2076949 100644
--- a/chrome/browser/extensions/extension_uitest.cc
+++ b/chrome/browser/extensions/extension_uitest.cc
@@ -57,10 +57,8 @@ class ExtensionUITest : public ExternalTabUITest {
  public:
    explicit ExtensionUITest(const std::string& extension_path)
       : loop_(MessageLoop::current()) {
-    FilePath filename(test_data_directory_);
-    filename = filename.AppendASCII(extension_path);
-    launch_arguments_.AppendSwitchWithValue(switches::kLoadExtension,
-                                            filename.value());
+    FilePath filename = test_data_directory_.AppendASCII(extension_path);
+    launch_arguments_.AppendSwitchPath(switches::kLoadExtension, filename);
     functions_enabled_.push_back("*");
   }
 
diff --git a/chrome/browser/first_run_win.cc b/chrome/browser/first_run_win.cc
index 32866ff..38b5b66 100644
--- a/chrome/browser/first_run_win.cc
+++ b/chrome/browser/first_run_win.cc
@@ -682,12 +682,13 @@ bool FirstRun::ImportSettings(Profile* profile, int browser_type,
                               HWND parent_window) {
   const CommandLine& cmdline = *CommandLine::ForCurrentProcess();
   CommandLine import_cmd(cmdline.GetProgram());
-  // Propagate user data directory switch.
-  if (cmdline.HasSwitch(switches::kUserDataDir)) {
-    import_cmd.AppendSwitchWithValue(
-        switches::kUserDataDir,
-        cmdline.GetSwitchValueASCII(switches::kUserDataDir));
-  }
+
+  const char* kSwitchNames[] = {
+    switches::kUserDataDir,
+    switches::kChromeFrame,
+    switches::kCountry,
+  };
+  import_cmd.CopySwitchesFrom(cmdline, kSwitchNames, arraysize(kSwitchNames));
 
   // Since ImportSettings is called before the local state is stored on disk
   // we pass the language as an argument.  GetApplicationLocale checks the
@@ -706,15 +707,6 @@ bool FirstRun::ImportSettings(Profile* profile, int browser_type,
         switches::kImportFromFile, import_bookmarks_path.c_str());
   }
 
-  if (cmdline.HasSwitch(switches::kChromeFrame)) {
-    import_cmd.AppendSwitch(switches::kChromeFrame);
-  }
-
-  if (cmdline.HasSwitch(switches::kCountry)) {
-    import_cmd.AppendSwitchWithValue(switches::kCountry,
-      cmdline.GetSwitchValueASCII(switches::kCountry));
-  }
-
   // Time to launch the process that is going to do the import.
   base::ProcessHandle import_process;
   if (!base::LaunchApp(import_cmd, false, false, &import_process))
diff --git a/chrome/browser/gpu_process_host.cc b/chrome/browser/gpu_process_host.cc
index cdf1102..03222fd 100644
--- a/chrome/browser/gpu_process_host.cc
+++ b/chrome/browser/gpu_process_host.cc
@@ -90,19 +90,15 @@ bool GpuProcessHost::Init() {
                                   ASCIIToWide(channel_id()));
 
   // Propagate relevant command line switches.
-  static const char* const switch_names[] = {
+  static const char* const kSwitchNames[] = {
     switches::kUseGL,
+    switches::kDisableLogging,
+    switches::kEnableLogging,
+    switches::kGpuStartupDialog,
+    switches::kLoggingLevel,
   };
-
-  for (size_t i = 0; i < arraysize(switch_names); ++i) {
-    if (browser_command_line.HasSwitch(switch_names[i])) {
-      cmd_line->AppendSwitchWithValue(switch_names[i],
-          browser_command_line.GetSwitchValueASCII(switch_names[i]));
-    }
-  }
-
-  const CommandLine& browser_cmd_line = *CommandLine::ForCurrentProcess();
-  PropagateBrowserCommandLineToGpu(browser_cmd_line, cmd_line);
+  cmd_line->CopySwitchesFrom(browser_command_line, kSwitchNames,
+                             arraysize(kSwitchNames));
 
   // If specified, prepend a launcher program to the command line.
   if (!gpu_launcher.empty())
@@ -215,26 +211,6 @@ void GpuProcessHost::ReplyToRenderer(
   filter->Send(message);
 }
 
-void GpuProcessHost::PropagateBrowserCommandLineToGpu(
-    const CommandLine& browser_cmd,
-    CommandLine* gpu_cmd) const {
-  // Propagate the following switches to the GPU process command line (along
-  // with any associated values) if present in the browser command line.
-  static const char* const switch_names[] = {
-    switches::kDisableLogging,
-    switches::kEnableLogging,
-    switches::kGpuStartupDialog,
-    switches::kLoggingLevel,
-  };
-
-  for (size_t i = 0; i < arraysize(switch_names); ++i) {
-    if (browser_cmd.HasSwitch(switch_names[i])) {
-      gpu_cmd->AppendSwitchWithValue(switch_names[i],
-          browser_cmd.GetSwitchValueASCII(switch_names[i]));
-    }
-  }
-}
-
 URLRequestContext* GpuProcessHost::GetRequestContext(
     uint32 request_id,
     const ViewHostMsg_Resource_Request& request_data) {
diff --git a/chrome/browser/gpu_process_host.h b/chrome/browser/gpu_process_host.h
index 662bae8..c81b565 100644
--- a/chrome/browser/gpu_process_host.h
+++ b/chrome/browser/gpu_process_host.h
@@ -92,12 +92,6 @@ class GpuProcessHost : public BrowserChildProcessHost {
   void ReplyToRenderer(const IPC::ChannelHandle& channel,
                        ResourceMessageFilter* filter);
 
-  // Copies applicable command line switches from the given |browser_cmd| line
-  // flags to the output |gpu_cmd| line flags. Not all switches will be
-  // copied over.
-  void PropagateBrowserCommandLineToGpu(const CommandLine& browser_cmd,
-                                        CommandLine* gpu_cmd) const;
-
   // ResourceDispatcherHost::Receiver implementation:
   virtual URLRequestContext* GetRequestContext(
       uint32 request_id,
diff --git a/chrome/browser/jumplist_win.cc b/chrome/browser/jumplist_win.cc
index e77b55c..1f434f6 100644
--- a/chrome/browser/jumplist_win.cc
+++ b/chrome/browser/jumplist_win.cc
@@ -422,10 +422,10 @@ bool UpdateJumpList(const wchar_t* app_id,
 
   // Retrieve the command-line switches of this process.
   CommandLine command_line(CommandLine::ARGUMENTS_ONLY);
-  std::wstring user_data_dir = CommandLine::ForCurrentProcess()->
-      GetSwitchValue(switches::kUserDataDir);
+  FilePath user_data_dir = CommandLine::ForCurrentProcess()->
+      GetSwitchValuePath(switches::kUserDataDir);
   if (!user_data_dir.empty())
-    command_line.AppendSwitchWithValue(switches::kUserDataDir, user_data_dir);
+    command_line.AppendSwitchPath(switches::kUserDataDir, user_data_dir);
 
   std::wstring chrome_switches = command_line.command_line_string();
 
diff --git a/chrome/browser/nacl_host/nacl_broker_host_win.cc b/chrome/browser/nacl_host/nacl_broker_host_win.cc
index f479030..2847e85 100644
--- a/chrome/browser/nacl_host/nacl_broker_host_win.cc
+++ b/chrome/browser/nacl_host/nacl_broker_host_win.cc
@@ -47,8 +47,7 @@ bool NaClBrokerHost::Init() {
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
       switches::kNaClBrokerProcess);
 
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-      ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
 
   BrowserChildProcessHost::Launch(FilePath(), cmd_line);
   return true;
diff --git a/chrome/browser/nacl_host/nacl_process_host.cc b/chrome/browser/nacl_host/nacl_process_host.cc
index 5c9d9da..dde5cb1 100644
--- a/chrome/browser/nacl_host/nacl_process_host.cc
+++ b/chrome/browser/nacl_host/nacl_process_host.cc
@@ -134,8 +134,7 @@ bool NaClProcessHost::LaunchSelLdr() {
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kNaClLoaderProcess);
 
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
 
   // On Windows we might need to start the broker process to launch a new loader
 #if defined(OS_WIN)
diff --git a/chrome/browser/net/chrome_url_request_context_unittest.cc b/chrome/browser/net/chrome_url_request_context_unittest.cc
index 7ba2dff..9f42e7b 100644
--- a/chrome/browser/net/chrome_url_request_context_unittest.cc
+++ b/chrome/browser/net/chrome_url_request_context_unittest.cc
@@ -25,25 +25,25 @@ TEST(ChromeURLRequestContextTest, CreateProxyConfigTest) {
   CommandLine no_proxy_extra_params(unused_path);
   no_proxy_extra_params.AppendSwitch(switches::kNoProxyServer);
   no_proxy_extra_params.AppendSwitchWithValue(switches::kProxyServer,
-      L"http://proxy:8888");
+      "http://proxy:8888");
   CommandLine single_proxy(unused_path);
   single_proxy.AppendSwitchWithValue(switches::kProxyServer,
-      L"http://proxy:8888");
+      "http://proxy:8888");
   CommandLine per_scheme_proxy(unused_path);
   per_scheme_proxy.AppendSwitchWithValue(switches::kProxyServer,
-      L"http=httpproxy:8888;ftp=ftpproxy:8889");
+      "http=httpproxy:8888;ftp=ftpproxy:8889");
   CommandLine per_scheme_proxy_bypass(unused_path);
   per_scheme_proxy_bypass.AppendSwitchWithValue(switches::kProxyServer,
-      L"http=httpproxy:8888;ftp=ftpproxy:8889");
+      "http=httpproxy:8888;ftp=ftpproxy:8889");
   per_scheme_proxy_bypass.AppendSwitchWithValue(
       switches::kProxyBypassList,
-      L".google.com, foo.com:99, 1.2.3.4:22, 127.0.0.1/8");
+      ".google.com, foo.com:99, 1.2.3.4:22, 127.0.0.1/8");
   CommandLine with_pac_url(unused_path);
   with_pac_url.AppendSwitchWithValue(switches::kProxyPacUrl,
-      L"http://wpad/wpad.dat");
+      "http://wpad/wpad.dat");
   with_pac_url.AppendSwitchWithValue(
       switches::kProxyBypassList,
-      L".google.com, foo.com:99, 1.2.3.4:22, 127.0.0.1/8");
+      ".google.com, foo.com:99, 1.2.3.4:22, 127.0.0.1/8");
   CommandLine with_auto_detect(unused_path);
   with_auto_detect.AppendSwitch(switches::kProxyAutoDetect);
 
diff --git a/chrome/browser/plugin_process_host.cc b/chrome/browser/plugin_process_host.cc
index 7c2aeb0..d6380cc 100644
--- a/chrome/browser/plugin_process_host.cc
+++ b/chrome/browser/plugin_process_host.cc
@@ -363,15 +363,14 @@ bool PluginProcessHost::Init(const WebPluginInfo& info,
   // in process listings using native process management tools.
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kPluginProcess);
-  cmd_line->AppendSwitchWithValue(switches::kPluginPath,
-                                  info.path.ToWStringHack());
+  cmd_line->AppendSwitchPath(switches::kPluginPath, info.path);
 
   if (logging::DialogsAreSuppressed())
     cmd_line->AppendSwitch(switches::kNoErrorDialogs);
 
   // Propagate the following switches to the plugin command line (along with
   // any associated values) if present in the browser command line
-  static const char* const switch_names[] = {
+  static const char* const kSwitchNames[] = {
     switches::kPluginStartupDialog,
     switches::kNoSandbox,
     switches::kSafePlugins,
@@ -396,13 +395,8 @@ bool PluginProcessHost::Init(const WebPluginInfo& info,
 #endif
   };
 
-  for (size_t i = 0; i < arraysize(switch_names); ++i) {
-    if (browser_command_line.HasSwitch(switch_names[i])) {
-      cmd_line->AppendSwitchWithValue(
-          switch_names[i],
-          browser_command_line.GetSwitchValueASCII(switch_names[i]));
-    }
-  }
+  cmd_line->CopySwitchesFrom(browser_command_line, kSwitchNames,
+                             arraysize(kSwitchNames));
 
   // If specified, prepend a launcher program to the command line.
   if (!plugin_launcher.empty())
@@ -415,13 +409,12 @@ bool PluginProcessHost::Init(const WebPluginInfo& info,
   }
 
   // Gears requires the data dir to be available on startup.
-  std::wstring data_dir =
-    PluginService::GetInstance()->GetChromePluginDataDir().ToWStringHack();
+  FilePath data_dir =
+    PluginService::GetInstance()->GetChromePluginDataDir();
   DCHECK(!data_dir.empty());
-  cmd_line->AppendSwitchWithValue(switches::kPluginDataDir, data_dir);
+  cmd_line->AppendSwitchPath(switches::kPluginDataDir, data_dir);
 
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
 
   SetCrashReporterCommandLine(cmd_line);
 
diff --git a/chrome/browser/pref_service_uitest.cc b/chrome/browser/pref_service_uitest.cc
index 87dcb2c..2f8f4e0 100644
--- a/chrome/browser/pref_service_uitest.cc
+++ b/chrome/browser/pref_service_uitest.cc
@@ -49,8 +49,7 @@ class PreferenceServiceTest : public UITest {
         FILE_ATTRIBUTE_NORMAL));
 #endif
 
-    launch_arguments_.AppendSwitchWithValue(switches::kUserDataDir,
-                                            tmp_profile_.ToWStringHack());
+    launch_arguments_.AppendSwitchPath(switches::kUserDataDir, tmp_profile_);
   }
 
   bool LaunchAppWithProfile() {
diff --git a/chrome/browser/printing/printing_layout_uitest.cc b/chrome/browser/printing/printing_layout_uitest.cc
index db20963..4d35c75 100644
--- a/chrome/browser/printing/printing_layout_uitest.cc
+++ b/chrome/browser/printing/printing_layout_uitest.cc
@@ -28,10 +28,8 @@ const wchar_t kDocRoot[] = L"chrome/test/data";
 class PrintingLayoutTest : public PrintingTest<UITest> {
  public:
   PrintingLayoutTest() {
-    emf_path_ = browser_directory_;
-    emf_path_ = emf_path_.AppendASCII("metafile_dumps");
-    launch_arguments_.AppendSwitchWithValue("debug-print",
-                                            L'"' + emf_path_.value() + L'"');
+    emf_path_ = browser_directory_.AppendASCII("metafile_dumps");
+    launch_arguments_.AppendSwitchPath("debug-print", emf_path_);
     show_window_ = true;
   }
 
diff --git a/chrome/browser/process_singleton_uitest.cc b/chrome/browser/process_singleton_uitest.cc
index ee8756a..8b7da6b 100644
--- a/chrome/browser/process_singleton_uitest.cc
+++ b/chrome/browser/process_singleton_uitest.cc
@@ -62,8 +62,7 @@ class ChromeStarter : public base::RefCountedThreadSafe<ChromeStarter> {
 
     FilePath user_data_directory;
     PathService::Get(chrome::DIR_USER_DATA, &user_data_directory);
-    command_line.AppendSwitchWithValue(switches::kUserDataDir,
-                                       user_data_directory.ToWStringHack());
+    command_line.AppendSwitchPath(switches::kUserDataDir, user_data_directory);
 
     if (first_run)
       command_line.AppendSwitch(switches::kFirstRun);
diff --git a/chrome/browser/profile_import_process_host.cc b/chrome/browser/profile_import_process_host.cc
index 84a2684..eaeb6dc 100644
--- a/chrome/browser/profile_import_process_host.cc
+++ b/chrome/browser/profile_import_process_host.cc
@@ -87,8 +87,7 @@ bool ProfileImportProcessHost::StartProcess() {
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kProfileImportProcess);
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
 
   SetCrashReporterCommandLine(cmd_line);
 
diff --git a/chrome/browser/renderer_host/browser_render_process_host.cc b/chrome/browser/renderer_host/browser_render_process_host.cc
index 1f87fca..2506617 100644
--- a/chrome/browser/renderer_host/browser_render_process_host.cc
+++ b/chrome/browser/renderer_host/browser_render_process_host.cc
@@ -331,8 +331,7 @@ bool BrowserRenderProcessHost::Init(bool is_extensions_process,
     if (!renderer_prefix.empty())
       cmd_line->PrependWrapper(renderer_prefix);
     AppendRendererCommandLine(cmd_line);
-    cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                    ASCIIToWide(channel_id));
+    cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id);
 
     // Spawn the child process asynchronously to avoid blocking the UI thread.
     // As long as there's no renderer prefix, we can use the zygote process
@@ -459,7 +458,7 @@ void BrowserRenderProcessHost::AppendRendererCommandLine(
 
   // Pass on the browser locale.
   const std::string locale = g_browser_process->GetApplicationLocale();
-  command_line->AppendSwitchWithValue(switches::kLang, ASCIIToWide(locale));
+  command_line->AppendSwitchWithValue(switches::kLang, locale);
 
   // If we run FieldTrials, we want to pass to their state to the renderer so
   // that it can act in accordance with each state, or record histograms
@@ -475,10 +474,8 @@ void BrowserRenderProcessHost::AppendRendererCommandLine(
 
   FilePath user_data_dir =
       browser_command_line.GetSwitchValuePath(switches::kUserDataDir);
-
   if (!user_data_dir.empty())
-    command_line->AppendSwitchWithValue(switches::kUserDataDir,
-                                        user_data_dir.value());
+    command_line->AppendSwitchPath(switches::kUserDataDir, user_data_dir);
 #if defined(OS_CHROMEOS)
   const std::string& profile =
       browser_command_line.GetSwitchValueASCII(switches::kProfile);
@@ -492,7 +489,7 @@ void BrowserRenderProcessHost::PropagateBrowserCommandLineToRenderer(
     CommandLine* renderer_cmd) const {
   // Propagate the following switches to the renderer command line (along
   // with any associated values) if present in the browser command line.
-  static const char* const switch_names[] = {
+  static const char* const kSwitchNames[] = {
     switches::kRendererAssertTest,
 #if !defined(OFFICIAL_BUILD)
     switches::kRendererCheckFalseTest,
@@ -580,13 +577,8 @@ void BrowserRenderProcessHost::PropagateBrowserCommandLineToRenderer(
     switches::kEnableClickToPlay,
     switches::kPrelaunchGpuProcess,
   };
-
-  for (size_t i = 0; i < arraysize(switch_names); ++i) {
-    if (browser_cmd.HasSwitch(switch_names[i])) {
-      renderer_cmd->AppendSwitchWithValue(switch_names[i],
-          browser_cmd.GetSwitchValueASCII(switch_names[i]));
-    }
-  }
+  renderer_cmd->CopySwitchesFrom(browser_cmd, kSwitchNames,
+                                 arraysize(kSwitchNames));
 
   // Disable databases in incognito mode.
   if (profile()->IsOffTheRecord() &&
diff --git a/chrome/browser/utility_process_host.cc b/chrome/browser/utility_process_host.cc
index 857c38d..dbcf94b 100644
--- a/chrome/browser/utility_process_host.cc
+++ b/chrome/browser/utility_process_host.cc
@@ -80,8 +80,7 @@ bool UtilityProcessHost::StartProcess(const FilePath& exposed_dir) {
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kUtilityProcess);
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
   std::string locale = g_browser_process->GetApplicationLocale();
   cmd_line->AppendSwitchWithValue(switches::kLang, locale);
 
@@ -114,8 +113,7 @@ bool UtilityProcessHost::StartProcess(const FilePath& exposed_dir) {
         switches::kUtilityCmdPrefix));
   }
 
-  cmd_line->AppendSwitchWithValue(switches::kUtilityProcessAllowedDir,
-                                  exposed_dir.value().c_str());
+  cmd_line->AppendSwitchPath(switches::kUtilityProcessAllowedDir, exposed_dir);
 #endif
 
   Launch(
diff --git a/chrome/browser/worker_host/worker_process_host.cc b/chrome/browser/worker_host/worker_process_host.cc
index 762a0c5..f995cbd 100644
--- a/chrome/browser/worker_host/worker_process_host.cc
+++ b/chrome/browser/worker_host/worker_process_host.cc
@@ -107,8 +107,7 @@ bool WorkerProcessHost::Init() {
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kWorkerProcess);
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
   SetCrashReporterCommandLine(cmd_line);
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -140,8 +139,7 @@ bool WorkerProcessHost::Init() {
     const std::wstring level =
         CommandLine::ForCurrentProcess()->GetSwitchValue(
             switches::kLoggingLevel);
-    cmd_line->AppendSwitchWithValue(
-        switches::kLoggingLevel, level);
+    cmd_line->AppendSwitchWithValue(switches::kLoggingLevel, level);
   }
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
diff --git a/chrome/browser/zygote_host_linux.cc b/chrome/browser/zygote_host_linux.cc
index 49c93c2..983e2ce 100644
--- a/chrome/browser/zygote_host_linux.cc
+++ b/chrome/browser/zygote_host_linux.cc
@@ -96,16 +96,9 @@ void ZygoteHost::Init(const std::string& sandbox_cmd) {
 #else
     switches::kEnableSeccompSandbox,
 #endif
-    NULL
   };
-  for (const char** sw = kForwardSwitches; *sw; sw++) {
-    if (browser_command_line.HasSwitch(*sw)) {
-      // Always append with value for those switches which need it; it does no
-      // harm for those which don't.
-      cmd_line.AppendSwitchWithValue(*sw,
-          browser_command_line.GetSwitchValueASCII(*sw));
-    }
-  }
+  cmd_line.CopySwitchesFrom(browser_command_line, kForwardSwitches,
+                            arraysize(kForwardSwitches));
 
   sandbox_binary_ = sandbox_cmd.c_str();
   struct stat st;
diff --git a/chrome/common/nacl_cmd_line.cc b/chrome/common/nacl_cmd_line.cc
index a54f196..82c2634 100644
--- a/chrome/common/nacl_cmd_line.cc
+++ b/chrome/common/nacl_cmd_line.cc
@@ -16,7 +16,7 @@ namespace nacl {
     // Propagate the following switches to the NaCl loader command line (along
     // with any associated values) if present in the browser command line.
     // TODO(gregoryd): check which flags of those below can be supported.
-    static const char* const switch_names[] = {
+    static const char* const kSwitchNames[] = {
       switches::kNoSandbox,
       switches::kTestNaClSandbox,
       switches::kDisableBreakpad,
@@ -28,13 +28,7 @@ namespace nacl {
       switches::kSilentDumpOnDCHECK,
       switches::kMemoryProfiling,
     };
-
-    for (size_t i = 0; i < arraysize(switch_names); ++i) {
-      if (browser_command_line.HasSwitch(switch_names[i])) {
-        cmd_line->AppendSwitchWithValue(
-          switch_names[i],
-          browser_command_line.GetSwitchValueASCII(switch_names[i]));
-      }
-    }
+    cmd_line->CopySwitchesFrom(browser_command_line, kSwitchNames,
+                               arraysize(kSwitchNames));
   }
 }
diff --git a/chrome/renderer/renderer_main_unittest.cc b/chrome/renderer/renderer_main_unittest.cc
index a63b0a6..4b561f8 100644
--- a/chrome/renderer/renderer_main_unittest.cc
+++ b/chrome/renderer/renderer_main_unittest.cc
@@ -79,7 +79,7 @@ MULTIPROCESS_TEST_MAIN(SimpleRenderer) {
   SandboxInitWrapper dummy_sandbox_init;
   CommandLine cl(*CommandLine::ForCurrentProcess());
   cl.AppendSwitchWithValue(switches::kProcessChannelID,
-                           ASCIIToWide(kRendererTestChannelName));
+                           kRendererTestChannelName);
 
   MainFunctionParams dummy_params(cl, dummy_sandbox_init, NULL);
   return RendererMain(dummy_params);
diff --git a/chrome/service/service_utility_process_host.cc b/chrome/service/service_utility_process_host.cc
index e465eb2..3776bc0 100644
--- a/chrome/service/service_utility_process_host.cc
+++ b/chrome/service/service_utility_process_host.cc
@@ -83,8 +83,7 @@ bool ServiceUtilityProcessHost::StartProcess() {
   CommandLine cmd_line(exe_path);
   cmd_line.AppendSwitchWithValue(switches::kProcessType,
                                  switches::kUtilityProcess);
-  cmd_line.AppendSwitchWithValue(switches::kProcessChannelID,
-                                 ASCIIToWide(channel_id()));
+  cmd_line.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
   cmd_line.AppendSwitch(switches::kLang);
 
   return Launch(&cmd_line);
diff --git a/chrome/test/automation/automation_proxy_uitest.cc b/chrome/test/automation/automation_proxy_uitest.cc
index ccdff3f..a16ac12 100644
--- a/chrome/test/automation/automation_proxy_uitest.cc
+++ b/chrome/test/automation/automation_proxy_uitest.cc
@@ -45,7 +45,7 @@ class AutomationProxyTest : public UITest {
   AutomationProxyTest() {
     dom_automation_enabled_ = true;
     launch_arguments_.AppendSwitchWithValue(switches::kLang,
-                                            L"en-US");
+                                            "en-US");
   }
 };
 
diff --git a/chrome/test/in_process_browser_test.cc b/chrome/test/in_process_browser_test.cc
index 0cbb39d..b8b8d90 100644
--- a/chrome/test/in_process_browser_test.cc
+++ b/chrome/test/in_process_browser_test.cc
@@ -136,15 +136,13 @@ void InProcessBrowserTest::SetUp() {
   // Turn off tip loading for tests; see http://crbug.com/17725
   command_line->AppendSwitch(switches::kDisableWebResources);
 
-  command_line->AppendSwitchWithValue(switches::kUserDataDir,
-                                      user_data_dir.ToWStringHack());
+  command_line->AppendSwitchPath(switches::kUserDataDir, user_data_dir);
 
   // Don't show the first run ui.
   command_line->AppendSwitch(switches::kNoFirstRun);
 
   // This is a Browser test.
-  command_line->AppendSwitchWithValue(switches::kTestType,
-                                      ASCIIToWide(kBrowserTestType));
+  command_line->AppendSwitchWithValue(switches::kTestType, kBrowserTestType);
 
   // Single-process mode is not set in BrowserMain so it needs to be processed
   // explicitly.
@@ -155,8 +153,8 @@ void InProcessBrowserTest::SetUp() {
 #if defined(OS_WIN)
   // The Windows sandbox requires that the browser and child processes are the
   // same binary.  So we launch browser_process.exe which loads chrome.dll
-  command_line->AppendSwitchWithValue(switches::kBrowserSubprocessPath,
-                                      command_line->GetProgram().value());
+  command_line->AppendSwitchPath(switches::kBrowserSubprocessPath,
+                                 command_line->GetProgram());
 #else
   // Explicitly set the path of the binary used for child processes, otherwise
   // they'll try to use browser_tests which doesn't contain ChromeMain.
@@ -165,8 +163,8 @@ void InProcessBrowserTest::SetUp() {
   subprocess_path = subprocess_path.DirName();
   subprocess_path = subprocess_path.AppendASCII(WideToASCII(
       chrome::kBrowserProcessExecutablePath));
-  command_line->AppendSwitchWithValue(switches::kBrowserSubprocessPath,
-                                      subprocess_path.ToWStringHack());
+  command_line->AppendSwitchPath(switches::kBrowserSubprocessPath,
+                                 subprocess_path);
 #endif
 
   // Enable warning level logging so that we can see when bad stuff happens.
diff --git a/chrome/test/memory_test/memory_test.cc b/chrome/test/memory_test/memory_test.cc
index 079e0a4..249cf16 100644
--- a/chrome/test/memory_test/memory_test.cc
+++ b/chrome/test/memory_test/memory_test.cc
@@ -116,8 +116,7 @@ class MemoryTest : public UITest {
       browser_directory_ = browser_dir;
     }
 
-    launch_arguments_.AppendSwitchWithValue(switches::kUserDataDir,
-                                            user_data_dir_.ToWStringHack());
+    launch_arguments_.AppendSwitchPath(switches::kUserDataDir, user_data_dir_);
     UITest::SetUp();
   }
 
diff --git a/chrome/test/nacl/nacl_sandbox_test.cc b/chrome/test/nacl/nacl_sandbox_test.cc
index 41aa97a..2517403 100644
--- a/chrome/test/nacl/nacl_sandbox_test.cc
+++ b/chrome/test/nacl/nacl_sandbox_test.cc
@@ -18,18 +18,16 @@ const FilePath::CharType kSrpcHwHtmlFileName[] =
 
 NaClSandboxTest::NaClSandboxTest() : NaClTest() {
   // Append the --test-nacl-sandbox=$TESTDLL flag before launching.
-  FilePath dylibDir;
-  PathService::Get(base::DIR_EXE, &dylibDir);
+  FilePath dylib_dir;
+  PathService::Get(base::DIR_EXE, &dylib_dir);
 #if defined(OS_MACOSX)
-  dylibDir = dylibDir.AppendASCII("libnacl_security_tests.dylib");
-  launch_arguments_.AppendSwitchWithValue(switches::kTestNaClSandbox,
-                                          dylibDir.value());
+  dylib_dir = dylib_dir.AppendASCII("libnacl_security_tests.dylib");
+  launch_arguments_.AppendSwitchPath(switches::kTestNaClSandbox, dylib_dir);
 #elif defined(OS_WIN)
   // Let the NaCl process detect if it is 64-bit or not and hack on
   // the appropriate suffix to this dll.
-  dylibDir = dylibDir.AppendASCII("nacl_security_tests");
-  launch_arguments_.AppendSwitchWithValue(switches::kTestNaClSandbox,
-                                          dylibDir.value());
+  dylib_dir = dylib_dir.AppendASCII("nacl_security_tests");
+  launch_arguments_.AppendSwitchPath(switches::kTestNaClSandbox, dylib_dir);
 #elif defined(OS_LINUX)
   // We currently do not test the Chrome Linux SUID or seccomp sandboxes.
 #endif
diff --git a/chrome/test/page_cycler/page_cycler_test.cc b/chrome/test/page_cycler/page_cycler_test.cc
index 1f5b49a..45bf07a 100644
--- a/chrome/test/page_cycler/page_cycler_test.cc
+++ b/chrome/test/page_cycler/page_cycler_test.cc
@@ -163,7 +163,7 @@ class PageCyclerTest : public UITest {
 
     // Expose garbage collection for the page cycler tests.
     launch_arguments_.AppendSwitchWithValue(switches::kJavaScriptFlags,
-                                            L"--expose_gc");
+                                            "--expose_gc");
 #if defined(OS_MACOSX)
     static rlim_t initial_fd_limit = GetFileDescriptorLimit();
     fd_limit_ = initial_fd_limit;
diff --git a/chrome/test/plugin/plugin_test.cpp b/chrome/test/plugin/plugin_test.cpp
index d8c81a5..80643b7 100644
--- a/chrome/test/plugin/plugin_test.cpp
+++ b/chrome/test/plugin/plugin_test.cpp
@@ -65,7 +65,7 @@ class PluginTest : public UITest {
       launch_arguments_.AppendSwitch(kUseOldWMPPluginSwitch);
     } else if (strcmp(test_info->name(), "FlashSecurity") == 0) {
       launch_arguments_.AppendSwitchWithValue(switches::kTestSandbox,
-                                              L"security_tests.dll");
+                                              "security_tests.dll");
     }
 
     UITest::SetUp();
diff --git a/chrome/test/ui/npapi_test_helper.cc b/chrome/test/ui/npapi_test_helper.cc
index 18e71a0..2bf6f10 100644
--- a/chrome/test/ui/npapi_test_helper.cc
+++ b/chrome/test/ui/npapi_test_helper.cc
@@ -49,8 +49,8 @@ void NPAPITesterBase::SetUp() {
 #if defined(OS_MACOSX)
   // The plugins directory isn't read by default on the Mac, so it needs to be
   // explicitly registered.
-  launch_arguments_.AppendSwitchWithValue(switches::kExtraPluginDir,
-                                          plugins_directory.value());
+  launch_arguments_.AppendSwitchPath(switches::kExtraPluginDir,
+                                     plugins_directory);
 #endif
 
   UITest::SetUp();
diff --git a/chrome/test/ui/ppapi_uitest.cc b/chrome/test/ui/ppapi_uitest.cc
index 5cb4aa8..b012262 100644
--- a/chrome/test/ui/ppapi_uitest.cc
+++ b/chrome/test/ui/ppapi_uitest.cc
@@ -36,15 +36,10 @@ class PPAPITest : public UITest {
 
     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);
diff --git a/chrome/test/ui/sandbox_uitests.cc b/chrome/test/ui/sandbox_uitests.cc
index 85d4708..172028b 100644
--- a/chrome/test/ui/sandbox_uitests.cc
+++ b/chrome/test/ui/sandbox_uitests.cc
@@ -14,7 +14,7 @@ class SandboxTest : public UITest {
   // Launches chrome with the --test-sandbox=security_tests.dll flag.
   SandboxTest() : UITest() {
     launch_arguments_.AppendSwitchWithValue(switches::kTestSandbox,
-                                            L"security_tests.dll");
+                                            "security_tests.dll");
   }
 };
 
diff --git a/chrome/test/ui/ui_test.cc b/chrome/test/ui/ui_test.cc
index 3b92b99..f3eff50 100644
--- a/chrome/test/ui/ui_test.cc
+++ b/chrome/test/ui/ui_test.cc
@@ -336,7 +336,7 @@ void UITestBase::StartHttpServerWithPort(const FilePath& root_directory,
   ASSERT_TRUE(cmd_line.get());
   cmd_line->AppendSwitchWithValue("server", "start");
   cmd_line->AppendSwitch("register_cygwin");
-  cmd_line->AppendSwitchWithValue("root", root_directory.ToWStringHack());
+  cmd_line->AppendSwitchPath("root", root_directory);
 
   // For Windows 7, if we start the lighttpd server on the foreground mode,
   // it will mess up with the command window and cause conhost.exe to crash. To
@@ -1118,12 +1118,10 @@ bool UITestBase::LaunchBrowserHelper(const CommandLine& arguments,
   command_line.AppendSwitch(switches::kNoDefaultBrowserCheck);
 
   // This is a UI test.
-  command_line.AppendSwitchWithValue(switches::kTestType,
-                                     ASCIIToWide(kUITestType));
+  command_line.AppendSwitchWithValue(switches::kTestType, kUITestType);
 
   // Tell the browser to use a temporary directory just for this test.
-  command_line.AppendSwitchWithValue(switches::kUserDataDir,
-                                     user_data_dir().ToWStringHack());
+  command_line.AppendSwitchPath(switches::kUserDataDir, user_data_dir());
 
   // We need cookies on file:// for things like the page cycler.
   if (enable_file_cookies_)
@@ -1134,7 +1132,7 @@ bool UITestBase::LaunchBrowserHelper(const CommandLine& arguments,
 
   if (include_testing_id_) {
     command_line.AppendSwitchWithValue(switches::kTestingChannelID,
-                                       ASCIIToWide(server_->channel_id()));
+                                       server_->channel_id());
   }
 
   if (!show_error_dialogs_ &&
@@ -1156,14 +1154,12 @@ bool UITestBase::LaunchBrowserHelper(const CommandLine& arguments,
   if (disable_breakpad_)
     command_line.AppendSwitch(switches::kDisableBreakpad);
   if (!homepage_.empty())
-    command_line.AppendSwitchWithValue(switches::kHomePage,
-                                       homepage_);
+    command_line.AppendSwitchWithValue(switches::kHomePage, homepage_);
   // Don't try to fetch web resources during UI testing.
   command_line.AppendSwitch(switches::kDisableWebResources);
 
   if (!js_flags_.empty())
-    command_line.AppendSwitchWithValue(switches::kJavaScriptFlags,
-                                       js_flags_);
+    command_line.AppendSwitchWithValue(switches::kJavaScriptFlags, js_flags_);
   if (!log_level_.empty())
     command_line.AppendSwitchWithValue(switches::kLoggingLevel, log_level_);
 
@@ -1180,8 +1176,7 @@ bool UITestBase::LaunchBrowserHelper(const CommandLine& arguments,
 #endif
 
   if (!ui_test_name_.empty())
-    command_line.AppendSwitchWithValue(switches::kTestName,
-                                       ui_test_name_);
+    command_line.AppendSwitchWithValue(switches::kTestName, ui_test_name_);
 
   // The tests assume that file:// URIs can freely access other file:// URIs.
   command_line.AppendSwitch(switches::kAllowFileAccessFromFiles);
diff --git a/chrome/test/ui_test_utils.cc b/chrome/test/ui_test_utils.cc
index 8e11ebf..a1abccd 100644
--- a/chrome/test/ui_test_utils.cc
+++ b/chrome/test/ui_test_utils.cc
@@ -618,11 +618,10 @@ TestWebSocketServer::TestWebSocketServer(const FilePath& root_directory) {
   cmd_line->AppendSwitchWithValue("server", "start");
   cmd_line->AppendSwitch("chromium");
   cmd_line->AppendSwitch("register_cygwin");
-  cmd_line->AppendSwitchWithValue("root", root_directory.ToWStringHack());
+  cmd_line->AppendSwitchPath("root", root_directory);
   temp_dir_.CreateUniqueTempDir();
   websocket_pid_file_ = temp_dir_.path().AppendASCII("websocket.pid");
-  cmd_line->AppendSwitchWithValue("pidfile",
-                                  websocket_pid_file_.ToWStringHack());
+  cmd_line->AppendSwitchPath("pidfile", websocket_pid_file_);
   SetPythonPath();
   base::LaunchApp(*cmd_line.get(), true, false, NULL);
 }
@@ -664,8 +663,7 @@ TestWebSocketServer::~TestWebSocketServer() {
   scoped_ptr<CommandLine> cmd_line(CreateWebSocketServerCommandLine());
   cmd_line->AppendSwitchWithValue("server", "stop");
   cmd_line->AppendSwitch("chromium");
-  cmd_line->AppendSwitchWithValue("pidfile",
-                                  websocket_pid_file_.ToWStringHack());
+  cmd_line->AppendSwitchPath("pidfile", websocket_pid_file_);
   base::LaunchApp(*cmd_line.get(), true, false, NULL);
 }
 
diff --git a/chrome_frame/chrome_frame_automation.cc b/chrome_frame/chrome_frame_automation.cc
index 8909923..bed7be2 100644
--- a/chrome_frame/chrome_frame_automation.cc
+++ b/chrome_frame/chrome_frame_automation.cc
@@ -280,7 +280,7 @@ void ProxyFactory::CreateProxy(ProxyFactory::ProxyCacheEntry* entry,
   scoped_ptr<CommandLine> command_line(
       chrome_launcher::CreateLaunchCommandLine());
   command_line->AppendSwitchWithValue(switches::kAutomationClientChannelID,
-      ASCIIToWide(proxy->channel_id()));
+      proxy->channel_id());
 
   // Run Chrome in Chrome Frame mode. In practice, this modifies the paths
   // and registry keys that Chrome looks in via the BrowserDistribution
@@ -304,8 +304,7 @@ void ProxyFactory::CreateProxy(ProxyFactory::ProxyCacheEntry* entry,
     command_line->AppendSwitch(switches::kFullMemoryCrashReport);
 
   DLOG(INFO) << "Profile path: " << params.profile_path.value();
-  command_line->AppendSwitchWithValue(switches::kUserDataDir,
-      params.profile_path.value());
+  command_line->AppendSwitchPath(switches::kUserDataDir, params.profile_path);
 
   std::wstring command_line_string(command_line->command_line_string());
   // If there are any extra arguments, append them to the command line.
diff --git a/chrome_frame/chrome_launcher_unittest.cc b/chrome_frame/chrome_launcher_unittest.cc
index 835fc35..9511b40 100644
--- a/chrome_frame/chrome_launcher_unittest.cc
+++ b/chrome_frame/chrome_launcher_unittest.cc
@@ -20,7 +20,7 @@ TEST(ChromeLauncher, IsValidCommandLine) {
 
   CommandLine good(FilePath(L"dummy.exe"));
   good.AppendSwitch(switches::kNoFirstRun);  // in whitelist
-  good.AppendSwitchWithValue(switches::kUserDataDir, L"foo");  // in whitelist
+  good.AppendSwitchWithValue(switches::kUserDataDir, "foo");  // in whitelist
 
   EXPECT_TRUE(chrome_launcher::IsValidCommandLine(
       good.command_line_string().c_str()));
diff --git a/chrome_frame/chrome_tab.cc b/chrome_frame/chrome_tab.cc
index 920adfd..f7ff496 100644
--- a/chrome_frame/chrome_tab.cc
+++ b/chrome_frame/chrome_tab.cc
@@ -281,7 +281,7 @@ HRESULT SetupRunOnce() {
   if (run_once.Create(HKEY_CURRENT_USER, kRunOnce, KEY_READ | KEY_WRITE)) {
     CommandLine run_once_command(chrome_launcher::GetChromeExecutablePath());
     run_once_command.AppendSwitchWithValue(
-        switches::kAutomationClientChannelID, L"0");
+        switches::kAutomationClientChannelID, "0");
     run_once_command.AppendSwitch(switches::kChromeFrame);
     run_once.WriteValue(L"A", run_once_command.command_line_string().c_str());
   }