Make CommandLine into a normal object, with some statics for getting at the current process's command line.

One explicit goal of this change is to *not* deal with the string/wstring issues at the API on POSIX; the functions are the same as before, which means they remain as broken as before.  (I did try to fix the internals, though, so migrating the callers is now possible by adding platform-appropriate hooks.)

Review URL: http://codereview.chromium.org/18248


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8347 0039d316-1c4b-4281-b951-d872f2087c98

72 files changed, 295 insertions, 310 deletions

diff --git a/chrome/app/breakpad.cc b/chrome/app/breakpad.cc
index c0245ad..70aaf97 100644
--- a/chrome/app/breakpad.cc
+++ b/chrome/app/breakpad.cc
@@ -163,7 +163,7 @@ static DWORD __stdcall InitCrashReporterThread(void* param) {
   // we do it here so it can run in a separate thread.
   info->custom_info = GetCustomInfo(info->dll_path, info->process_type);
 
-  CommandLine command;
+  const CommandLine& command = *CommandLine::ForCurrentProcess();
   bool full_dump = command.HasSwitch(switches::kFullMemoryCrashReport);
   bool use_crash_service = command.HasSwitch(switches::kNoErrorDialogs) ||
                            GetEnvironmentVariable(L"CHROME_HEADLESS", NULL, 0);
@@ -238,7 +238,7 @@ void InitDefaultCrashCallback() {
 }
 
 void InitCrashReporter(std::wstring dll_path) {
-  CommandLine command;
+  const CommandLine& command = *CommandLine::ForCurrentProcess();
   if (!command.HasSwitch(switches::kDisableBreakpad)) {
     // Disable the message box for assertions.
     _CrtSetReportMode(_CRT_ASSERT, 0);
diff --git a/chrome/app/chrome_dll_main.cc b/chrome/app/chrome_dll_main.cc
index 48d5b21..29429d0 100644
--- a/chrome/app/chrome_dll_main.cc
+++ b/chrome/app/chrome_dll_main.cc
@@ -204,10 +204,12 @@ int ChromeMain(int argc, const char** argv) {
   base::ScopedNSAutoreleasePool autorelease_pool;
 
   // Initialize the command line.
-#if defined(OS_POSIX)
-  CommandLine::SetArgcArgv(argc, argv);
+#if defined(OS_WIN)
+  CommandLine::Init(0, NULL);
+#else
+  CommandLine::Init(argc, argv);
 #endif
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
 
   SetupCRT(parsed_command_line);
   
diff --git a/chrome/app/chrome_exe_main.cc b/chrome/app/chrome_exe_main.cc
index 85a3462..6399198 100644
--- a/chrome/app/chrome_exe_main.cc
+++ b/chrome/app/chrome_exe_main.cc
@@ -42,6 +42,8 @@ int APIENTRY wWinMain(HINSTANCE instance, HINSTANCE prev_instance,
   if (!sandbox_info.broker_services)
     sandbox_info.target_services = sandbox::SandboxFactory::GetTargetServices();
 
+  CommandLine::Init(0, NULL);
+
   const wchar_t* dll_name = L"chrome.dll";
 #if defined(GOOGLE_CHROME_BUILD)
   google_update::GoogleUpdateClient client;
diff --git a/chrome/app/chrome_main_uitest.cc b/chrome/app/chrome_main_uitest.cc
index 4217c3b..4689d27 100644
--- a/chrome/app/chrome_main_uitest.cc
+++ b/chrome/app/chrome_main_uitest.cc
@@ -35,7 +35,7 @@ TEST_F(ChromeMainTest, SecondLaunch) {
   include_testing_id_ = false;
   use_existing_browser_ = true;
 
-  LaunchBrowser(std::wstring(), false);
+  LaunchBrowser(CommandLine(L""), false);
 
   int window_count;
   ASSERT_TRUE(automation()->WaitForWindowCountToChange(1, &window_count,
diff --git a/chrome/browser/browser.cc b/chrome/browser/browser.cc
index 54f3789..3e12603 100644
--- a/chrome/browser/browser.cc
+++ b/chrome/browser/browser.cc
@@ -321,7 +321,7 @@ void Browser::SaveWindowPlacement(const gfx::Rect& bounds, bool maximized) {
 }
 
 gfx::Rect Browser::GetSavedWindowBounds() const {
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   bool record_mode = parsed_command_line.HasSwitch(switches::kRecordMode);
   bool playback_mode = parsed_command_line.HasSwitch(switches::kPlaybackMode);
   if (record_mode || playback_mode) {
@@ -343,7 +343,7 @@ gfx::Rect Browser::GetSavedWindowBounds() const {
 // TODO(beng): obtain maximized state some other way so we don't need to go
 //             through all this hassle.
 bool Browser::GetSavedMaximizedState() const {
-  if (CommandLine().HasSwitch(switches::kStartMaximized))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kStartMaximized))
     return true;
 
   gfx::Rect restored_bounds;
@@ -1489,7 +1489,7 @@ void Browser::OpenURLFromTab(TabContents* source,
   // TODO(creis): should this apply to applications?
   SiteInstance* instance = NULL;
   // Don't use this logic when "--process-per-tab" is specified.
-  if (!CommandLine().HasSwitch(switches::kProcessPerTab)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessPerTab)) {
     if (current_tab) {
       const WebContents* const web_contents = current_tab->AsWebContents();
       if (web_contents) {
diff --git a/chrome/browser/browser_init.cc b/chrome/browser/browser_init.cc
index eba5365..3a0794e 100644
--- a/chrome/browser/browser_init.cc
+++ b/chrome/browser/browser_init.cc
@@ -403,7 +403,8 @@ bool BrowserInit::LaunchWithProfile::Launch(Profile* profile,
   DCHECK(profile);
   profile_ = profile;
 
-  CommandLine parsed_command_line(command_line_);
+  CommandLine parsed_command_line(L"");
+  parsed_command_line.ParseFromString(command_line_);
   if (parsed_command_line.HasSwitch(switches::kDnsLogDetails))
     chrome_browser_net::EnableDnsDetailedLog(true);
   if (parsed_command_line.HasSwitch(switches::kDnsPrefetchDisable))
@@ -569,30 +570,27 @@ void BrowserInit::LaunchWithProfile::AddCrashedInfoBarIfNecessary(
 std::vector<GURL> BrowserInit::LaunchWithProfile::GetURLsFromCommandLine(
     const CommandLine& command_line, Profile* profile) {
   std::vector<GURL> urls;
-  if (command_line.GetLooseValueCount() > 0) {
-    for (CommandLine::LooseValueIterator iter =
-         command_line.GetLooseValuesBegin();
-         iter != command_line.GetLooseValuesEnd(); ++iter) {
-      std::wstring value = *iter;
-      // Handle Vista way of searching - "? <search-term>"
-      if (value.find(L"? ") == 0) {
-        const TemplateURL* const default_provider =
-            profile->GetTemplateURLModel()->GetDefaultSearchProvider();
-        if (!default_provider || !default_provider->url()) {
-          // No search provider available. Just treat this as regular URL.
-          urls.push_back(GURL(URLFixerUpper::FixupRelativeFile(cur_dir_,
-                                                               value)));
-          continue;
-        }
-        const TemplateURLRef* const search_url = default_provider->url();
-        DCHECK(search_url->SupportsReplacement());
-        urls.push_back(GURL(search_url->ReplaceSearchTerms(*default_provider,
-            value.substr(2), TemplateURLRef::NO_SUGGESTIONS_AVAILABLE,
-            std::wstring())));
-      } else {
-        // This will create a file URL or a regular URL.
-        urls.push_back(GURL(URLFixerUpper::FixupRelativeFile(cur_dir_, value)));
+  std::vector<std::wstring> params = command_line.GetLooseValues();
+  for (size_t i = 0; i < params.size(); ++i) {
+    const std::wstring& value = params[i];
+    // Handle Vista way of searching - "? <search-term>"
+    if (value.find(L"? ") == 0) {
+      const TemplateURL* const default_provider =
+          profile->GetTemplateURLModel()->GetDefaultSearchProvider();
+      if (!default_provider || !default_provider->url()) {
+        // No search provider available. Just treat this as regular URL.
+        urls.push_back(GURL(URLFixerUpper::FixupRelativeFile(cur_dir_,
+                                                             value)));
+        continue;
       }
+      const TemplateURLRef* const search_url = default_provider->url();
+      DCHECK(search_url->SupportsReplacement());
+      urls.push_back(GURL(search_url->ReplaceSearchTerms(*default_provider,
+          value.substr(2), TemplateURLRef::NO_SUGGESTIONS_AVAILABLE,
+          std::wstring())));
+    } else {
+      // This will create a file URL or a regular URL.
+      urls.push_back(GURL(URLFixerUpper::FixupRelativeFile(cur_dir_, value)));
     }
   }
   return urls;
@@ -633,7 +631,7 @@ bool BrowserInit::ProcessCommandLine(const CommandLine& parsed_command_line,
       CreateAutomationProvider<TestingAutomationProvider>(
           testing_channel_id,
           profile,
-          std::max(static_cast<int>(parsed_command_line.GetLooseValueCount()),
+          std::max(static_cast<int>(parsed_command_line.GetLooseValues().size()),
                    1));
     }
   }
@@ -651,7 +649,7 @@ bool BrowserInit::ProcessCommandLine(const CommandLine& parsed_command_line,
     // If there are any loose parameters, we expect each one to generate a
     // new tab; if there are none then we have no tabs
     size_t expected_tabs =
-        std::max(static_cast<int>(parsed_command_line.GetLooseValueCount()),
+        std::max(static_cast<int>(parsed_command_line.GetLooseValues().size()),
                  0);
     if (expected_tabs == 0) {
       silent_launch = true;
diff --git a/chrome/browser/browser_main.cc b/chrome/browser/browser_main.cc
index 2645013..29d984e 100644
--- a/chrome/browser/browser_main.cc
+++ b/chrome/browser/browser_main.cc
@@ -176,7 +176,7 @@ StringPiece NetResourceProvider(int key) {
 
 // Main routine for running as the Browser process.
 int BrowserMain(const MainFunctionParams& parameters) {
-  CommandLine& parsed_command_line = parameters.command_line_;
+  const CommandLine& parsed_command_line = parameters.command_line_;
 
   // WARNING: If we get a WM_ENDSESSION objects created on the stack here
   // are NOT deleted. If you need something to run during WM_ENDSESSION add it
@@ -327,10 +327,9 @@ int BrowserMain(const MainFunctionParams& parameters) {
       // --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.
-      std::wstring new_command_line =
-          parsed_command_line.command_line_string();
-      CommandLine::AppendSwitchWithValue(&new_command_line,
-          switches::kUserDataDir, user_data_dir);
+      CommandLine new_command_line = parsed_command_line;
+      new_command_line.AppendSwitchWithValue(switches::kUserDataDir,
+                                             user_data_dir);
       base::LaunchApp(new_command_line, false, false, NULL);
     }
 
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 20188cc1..3fa75d5 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -82,7 +82,7 @@ class BrowserProcessSubThread : public ChromeThread {
 
 }  // namespace
 
-BrowserProcessImpl::BrowserProcessImpl(CommandLine& command_line)
+BrowserProcessImpl::BrowserProcessImpl(const CommandLine& command_line)
     : created_resource_dispatcher_host_(false),
       created_metrics_service_(false),
       created_io_thread_(false),
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index 3b8732c..bcbb862 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -28,7 +28,7 @@ class NotificationService;
 // Real implementation of BrowserProcess that creates and returns the services.
 class BrowserProcessImpl : public BrowserProcess, public NonThreadSafe {
  public:
-  BrowserProcessImpl(CommandLine& command_line);
+  BrowserProcessImpl(const CommandLine& command_line);
   virtual ~BrowserProcessImpl();
 
   virtual void EndSession();
diff --git a/chrome/browser/browsing_instance.cc b/chrome/browser/browsing_instance.cc
index 527feb1a..f15deca 100644
--- a/chrome/browser/browsing_instance.cc
+++ b/chrome/browser/browsing_instance.cc
@@ -17,10 +17,11 @@ bool BrowsingInstance::ShouldUseProcessPerSite(const GURL& url) {
   // the case if the --process-per-site switch is specified, or in
   // process-per-site-instance for particular sites (e.g., the new tab page).
 
-  if (CommandLine().HasSwitch(switches::kProcessPerSite))
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kProcessPerSite))
     return true;
 
-  if (!CommandLine().HasSwitch(switches::kProcessPerTab)) {
+  if (!command_line.HasSwitch(switches::kProcessPerTab)) {
     // We are not in process-per-site or process-per-tab, so we must be in the
     // default (process-per-site-instance).  Only use the process-per-site
     // logic for particular sites that we want to consolidate.
diff --git a/chrome/browser/chrome_plugin_host.cc b/chrome/browser/chrome_plugin_host.cc
index 55f1dd1..f501764 100644
--- a/chrome/browser/chrome_plugin_host.cc
+++ b/chrome/browser/chrome_plugin_host.cc
@@ -640,8 +640,8 @@ CPProcessType STDCALL CPB_GetProcessType(CPID id) {
 }
 
 CPError STDCALL CPB_SendMessage(CPID id, const void *data, uint32 data_len) {
-  CommandLine cmd;
-  if (cmd.HasSwitch(switches::kGearsInRenderer)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kGearsInRenderer)) {
     ChromePluginLib* plugin = ChromePluginLib::FromCPID(id);
     CHECK(plugin);
 
diff --git a/chrome/browser/debugger/debugger_contents.cc b/chrome/browser/debugger/debugger_contents.cc
index a6dd254..c3d2e4b 100644
--- a/chrome/browser/debugger/debugger_contents.cc
+++ b/chrome/browser/debugger/debugger_contents.cc
@@ -40,7 +40,8 @@ class DebuggerHTMLSource : public ChromeURLDataManager::DataSource {
     }
 
     std::wstring debugger_path =
-        CommandLine().GetSwitchValue(switches::kJavaScriptDebuggerPath);
+        CommandLine::ForCurrentProcess()->GetSwitchValue(
+            switches::kJavaScriptDebuggerPath);
     std::string data_str;
     if (!debugger_path.empty() && file_util::PathExists(debugger_path)) {
       if (path.empty())
diff --git a/chrome/browser/first_run.cc b/chrome/browser/first_run.cc
index c6f4f29..8522a8b 100755
--- a/chrome/browser/first_run.cc
+++ b/chrome/browser/first_run.cc
@@ -450,8 +450,8 @@ bool DecodeImportParams(const std::wstring& encoded,
 
 bool FirstRun::ImportSettings(Profile* profile, int browser,
                               int items_to_import, HWND parent_window) {
-  CommandLine cmdline;
-  std::wstring import_cmd(cmdline.program());
+  const CommandLine& cmdline = *CommandLine::ForCurrentProcess();
+  CommandLine import_cmd(cmdline.program());
   // Propagate the following switches to the importer command line.
   static const wchar_t* const switch_names[] = {
     switches::kUserDataDir,
@@ -459,12 +459,12 @@ bool FirstRun::ImportSettings(Profile* profile, int browser,
   };
   for (int i = 0; i < arraysize(switch_names); ++i) {
     if (cmdline.HasSwitch(switch_names[i])) {
-      CommandLine::AppendSwitchWithValue(
-          &import_cmd, switch_names[i],
+      import_cmd.AppendSwitchWithValue(
+          switch_names[i],
           cmdline.GetSwitchValue(switch_names[i]));
     }
   }
-  CommandLine::AppendSwitchWithValue(&import_cmd, switches::kImport,
+  import_cmd.CommandLine::AppendSwitchWithValue(switches::kImport,
       EncodeImportParams(browser, items_to_import, parent_window));
 
   // Time to launch the process that is going to do the import.
diff --git a/chrome/browser/first_run.h b/chrome/browser/first_run.h
index 4332b8b..676bd49 100644
--- a/chrome/browser/first_run.h
+++ b/chrome/browser/first_run.h
@@ -105,7 +105,7 @@ class Upgrade {
 // so we don't fetch as we have no IO thread (see bug #1292702).
 class FirstRunBrowserProcess : public BrowserProcessImpl {
  public:
-  FirstRunBrowserProcess(CommandLine& command_line)
+  FirstRunBrowserProcess(const CommandLine& command_line)
       : BrowserProcessImpl(command_line) {
   }
   virtual ~FirstRunBrowserProcess() { }
diff --git a/chrome/browser/images_uitest.cc b/chrome/browser/images_uitest.cc
index cfe0938..0b5a4be 100644
--- a/chrome/browser/images_uitest.cc
+++ b/chrome/browser/images_uitest.cc
@@ -9,8 +9,10 @@
 class ImagesTest : public UITest {
  protected:
   ImagesTest() : UITest() {
-    launch_arguments_ = test_data_directory_;
-    file_util::AppendToPath(&launch_arguments_, L"animated-gifs.html");
+    std::wstring path = test_data_directory_;
+    file_util::AppendToPath(&path, L"animated-gifs.html");
+    launch_arguments_ = CommandLine(L"");
+    launch_arguments_.AppendLooseValue(path);
   }
 };
 
diff --git a/chrome/browser/locale_tests_uitest.cc b/chrome/browser/locale_tests_uitest.cc
index 5c20f76..d707705 100644
--- a/chrome/browser/locale_tests_uitest.cc
+++ b/chrome/browser/locale_tests_uitest.cc
@@ -7,21 +7,21 @@
 class LocaleTestsDa : public UITest {
  public:
   LocaleTestsDa() : UITest() {
-    launch_arguments_.append(L" --lang=da");
+    launch_arguments_.AppendSwitchWithValue(L"lang", L"da");
   }
 };
 
 class LocaleTestsHe : public UITest {
  public:
   LocaleTestsHe() : UITest() {
-    launch_arguments_.append(L" --lang=he");
+    launch_arguments_.AppendSwitchWithValue(L"lang", L"he");
   }
 };
 
 class LocaleTestsZhTw : public UITest {
  public:
   LocaleTestsZhTw() : UITest() {
-    launch_arguments_.append(L" --lang=zh-tw");
+    launch_arguments_.AppendSwitchWithValue(L"lang", L"zh-tw");
   }
 };
 
diff --git a/chrome/browser/net/chrome_url_request_context.cc b/chrome/browser/net/chrome_url_request_context.cc
index 5ba3f63..d834e57 100644
--- a/chrome/browser/net/chrome_url_request_context.cc
+++ b/chrome/browser/net/chrome_url_request_context.cc
@@ -23,7 +23,7 @@
 static net::ProxyInfo* CreateProxyInfo() {
   net::ProxyInfo* proxy_info = NULL;
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kProxyServer)) {
     proxy_info = new net::ProxyInfo();
     const std::wstring& proxy_server =
@@ -47,7 +47,7 @@ ChromeURLRequestContext* ChromeURLRequestContext::CreateOriginal(
   net::HttpCache* cache =
       new net::HttpCache(context->proxy_service_, disk_cache_path, 0);
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   bool record_mode = chrome::kRecordModeEnabled &&
                      command_line.HasSwitch(switches::kRecordMode);
   bool playback_mode = command_line.HasSwitch(switches::kPlaybackMode);
diff --git a/chrome/browser/plugin_process_host.cc b/chrome/browser/plugin_process_host.cc
index 50ca1b9..9da52d2 100644
--- a/chrome/browser/plugin_process_host.cc
+++ b/chrome/browser/plugin_process_host.cc
@@ -461,13 +461,11 @@ bool PluginProcessHost::Init(const FilePath& plugin_path,
   if (!PathService::Get(base::FILE_EXE, &exe_path))
     return false;
 
-  std::wstring cmd_line(L"\"");
-  cmd_line += exe_path;
-  cmd_line += L"\"";
+  CommandLine cmd_line(exe_path);
   if (logging::DialogsAreSuppressed())
-    CommandLine::AppendSwitch(&cmd_line, switches::kNoErrorDialogs);
+    cmd_line.AppendSwitch(switches::kNoErrorDialogs);
 
-  CommandLine browser_command_line;
+  const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
 
   // propagate the following switches to the plugin command line (along with
   // any associated values) if present in the browser command line
@@ -492,8 +490,8 @@ bool PluginProcessHost::Init(const FilePath& plugin_path,
 
   for (int i = 0; i < arraysize(switch_names); ++i) {
     if (browser_command_line.HasSwitch(switch_names[i])) {
-      CommandLine::AppendSwitchWithValue(
-          &cmd_line, switch_names[i],
+      cmd_line.AppendSwitchWithValue(
+          switch_names[i],
           browser_command_line.GetSwitchValue(switch_names[i]));
     }
   }
@@ -501,26 +499,26 @@ bool PluginProcessHost::Init(const FilePath& plugin_path,
   // If specified, prepend a launcher program to the command line.
   std::wstring plugin_launcher =
       browser_command_line.GetSwitchValue(switches::kPluginLauncher);
-  if (!plugin_launcher.empty())
-    cmd_line = plugin_launcher + L" " + cmd_line;
+  if (!plugin_launcher.empty()) {
+    CommandLine new_cmd_line = CommandLine(plugin_launcher);
+    new_cmd_line.AppendArguments(cmd_line, true);
+    cmd_line = new_cmd_line;
+  }
 
   if (!locale.empty()) {
     // Pass on the locale so the null plugin will use the right language in the
     // prompt to install the desired plugin.
-    CommandLine::AppendSwitchWithValue(&cmd_line, switches::kLang, locale);
+    cmd_line.AppendSwitchWithValue(switches::kLang, locale);
   }
 
-  CommandLine::AppendSwitchWithValue(&cmd_line,
-                                     switches::kProcessType,
-                                     switches::kPluginProcess);
+  cmd_line.AppendSwitchWithValue(switches::kProcessType,
+                                 switches::kPluginProcess);
 
-  CommandLine::AppendSwitchWithValue(&cmd_line,
-                                     switches::kProcessChannelID,
-                                     channel_id_);
+  cmd_line.AppendSwitchWithValue(switches::kProcessChannelID,
+                                 channel_id_);
 
-  CommandLine::AppendSwitchWithValue(&cmd_line,
-                                     switches::kPluginPath,
-                                     plugin_path.ToWStringHack());
+  cmd_line.AppendSwitchWithValue(switches::kPluginPath,
+                                 plugin_path.ToWStringHack());
 
   bool in_sandbox = !browser_command_line.HasSwitch(switches::kNoSandbox) &&
                     browser_command_line.HasSwitch(switches::kSafePlugins);
@@ -550,8 +548,10 @@ bool PluginProcessHost::Init(const FilePath& plugin_path,
       return false;
     }
 
-    result = broker_service->SpawnTarget(exe_path.c_str(),
-                                         cmd_line.c_str(), policy, &target);
+    result =
+        broker_service->SpawnTarget(exe_path.c_str(),
+                                    cmd_line.command_line_string().c_str(),
+                                    policy, &target);
     policy->Release();
     if (sandbox::SBOX_ALL_OK != result)
       return false;
diff --git a/chrome/browser/printing/printing_layout_uitest.cc b/chrome/browser/printing/printing_layout_uitest.cc
index 086c2b9..038ee5d 100644
--- a/chrome/browser/printing/printing_layout_uitest.cc
+++ b/chrome/browser/printing/printing_layout_uitest.cc
@@ -204,10 +204,7 @@ class PrintingLayoutTest : public PrintingTest<UITest> {
   PrintingLayoutTest() {
     emf_path_ = browser_directory_;
     file_util::AppendToPath(&emf_path_, L"emf_dumps");
-    std::wstring arg(L" --debug-print=\"");
-    arg += emf_path_;
-    arg += L"\"";
-    launch_arguments_.append(arg);
+    launch_arguments_.AppendSwitchWithValue(L"debug-print", L'"' + emf_path_ + L'"');
     show_window_ = true;
   }
 
@@ -371,7 +368,7 @@ class PrintingLayoutTest : public PrintingTest<UITest> {
   }
 
   static bool GenerateFiles() {
-    return CommandLine().HasSwitch(kGenerateSwitch);
+    return CommandLine::ForCurrentProcess()->HasSwitch(kGenerateSwitch);
   }
 
   const std::wstring& emf_path() const { return emf_path_; }
diff --git a/chrome/browser/render_view_context_menu_controller.cc b/chrome/browser/render_view_context_menu_controller.cc
index bdb34e7..307bae4 100644
--- a/chrome/browser/render_view_context_menu_controller.cc
+++ b/chrome/browser/render_view_context_menu_controller.cc
@@ -475,7 +475,7 @@ void RenderViewContextMenuController::ExecuteCommand(int id) {
 }
 
 bool RenderViewContextMenuController::IsDevCommandEnabled(int id) const {
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kAlwaysEnableDevTools))
     return true;
 
diff --git a/chrome/browser/render_view_host_manager.cc b/chrome/browser/render_view_host_manager.cc
index 622df9e..05d07f5 100644
--- a/chrome/browser/render_view_host_manager.cc
+++ b/chrome/browser/render_view_host_manager.cc
@@ -232,7 +232,7 @@ void RenderViewHostManager::OnJavaScriptMessageBoxClosed(
 bool RenderViewHostManager::ShouldTransitionCrossSite() {
   // True if we are using process-per-site-instance (default) or
   // process-per-site (kProcessPerSite).
-  return !CommandLine().HasSwitch(switches::kProcessPerTab);
+  return !CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessPerTab);
 }
 
 SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
@@ -254,7 +254,7 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
   // NOTE: This can be removed once we have a way to transition between
   //       RenderViews in response to a link click.
   //
-  if (CommandLine().HasSwitch(switches::kProcessPerSite) &&
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessPerSite) &&
       entry.transition_type() == PageTransition::GENERATED)
     return curr_instance;
 
diff --git a/chrome/browser/render_widget_host_view_win.cc b/chrome/browser/render_widget_host_view_win.cc
index 4fd0f18..0aa756d 100644
--- a/chrome/browser/render_widget_host_view_win.cc
+++ b/chrome/browser/render_widget_host_view_win.cc
@@ -79,7 +79,8 @@ RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
       activatable_(true) {
   render_widget_host_->set_view(this);
   renderer_accessible_ =
-      CommandLine().HasSwitch(switches::kEnableRendererAccessibility);
+      CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableRendererAccessibility);
 }
 
 RenderWidgetHostViewWin::~RenderWidgetHostViewWin() {
diff --git a/chrome/browser/renderer_host/browser_render_process_host.cc b/chrome/browser/renderer_host/browser_render_process_host.cc
index 198d886..cb43eb9 100644
--- a/chrome/browser/renderer_host/browser_render_process_host.cc
+++ b/chrome/browser/renderer_host/browser_render_process_host.cc
@@ -167,7 +167,7 @@ bool BrowserRenderProcessHost::Init() {
                                 widget_helper_,
                                 profile()->GetSpellChecker());
 
-  CommandLine browser_command_line;
+  const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
 
   // setup IPC channel
   std::wstring channel_id = GenerateRandomChannelID(this);
@@ -188,10 +188,9 @@ bool BrowserRenderProcessHost::Init() {
   if (renderer_path.empty())
     if (!GetRendererPath(&renderer_path))
       return false;
-  std::wstring cmd_line;
-  cmd_line = L"\"" + renderer_path + L"\"";
+  CommandLine cmd_line(renderer_path);
   if (logging::DialogsAreSuppressed())
-    CommandLine::AppendSwitch(&cmd_line, switches::kNoErrorDialogs);
+    cmd_line.AppendSwitch(switches::kNoErrorDialogs);
 
   // propagate the following switches to the renderer command line
   // (along with any associated values) if present in the browser command line
@@ -229,15 +228,14 @@ bool BrowserRenderProcessHost::Init() {
 
   for (int i = 0; i < arraysize(switch_names); ++i) {
     if (browser_command_line.HasSwitch(switch_names[i])) {
-      CommandLine::AppendSwitchWithValue(
-          &cmd_line, switch_names[i],
+      cmd_line.AppendSwitchWithValue(switch_names[i],
           browser_command_line.GetSwitchValue(switch_names[i]));
     }
   }
 
   // Pass on the browser locale.
   const std::wstring locale = g_browser_process->GetApplicationLocale();
-  CommandLine::AppendSwitchWithValue(&cmd_line, switches::kLang, locale);
+  cmd_line.AppendSwitchWithValue(switches::kLang, locale);
 
   bool in_sandbox = !browser_command_line.HasSwitch(switches::kNoSandbox);
   if (browser_command_line.HasSwitch(switches::kInProcessPlugins)) {
@@ -249,19 +247,17 @@ bool BrowserRenderProcessHost::Init() {
       DebugFlags::ProcessDebugFlags(&cmd_line,
                                     DebugFlags::RENDERER,
                                     in_sandbox);
-  CommandLine::AppendSwitchWithValue(&cmd_line,
-                                     switches::kProcessType,
-                                     switches::kRendererProcess);
+  cmd_line.AppendSwitchWithValue(switches::kProcessType,
+                                 switches::kRendererProcess);
 
-  CommandLine::AppendSwitchWithValue(&cmd_line,
-                                     switches::kProcessChannelID,
-                                     channel_id);
+  cmd_line.AppendSwitchWithValue(switches::kProcessChannelID,
+                                 channel_id);
 
   const std::wstring& profile_path =
       browser_command_line.GetSwitchValue(switches::kUserDataDir);
   if (!profile_path.empty())
-    CommandLine::AppendSwitchWithValue(&cmd_line, switches::kUserDataDir,
-                                       profile_path);
+    cmd_line.AppendSwitchWithValue(switches::kUserDataDir,
+                                   profile_path);
 
   bool run_in_process = run_renderer_in_process();
   if (run_in_process) {
@@ -286,7 +282,8 @@ bool BrowserRenderProcessHost::Init() {
         g_browser_process->local_state()->GetBoolean(
             prefs::kStartRenderersManually)) {
       std::wstring message =
-        L"Please start a renderer process using:\n" + cmd_line;
+          L"Please start a renderer process using:\n" +
+          cmd_line.command_line_string();
 
       // We don't know the owner window for BrowserRenderProcessHost and therefore we
       // pass a NULL HWND argument.
@@ -328,8 +325,7 @@ bool BrowserRenderProcessHost::Init() {
           return false;
         }
 
-        CommandLine command_line;
-        if (command_line.HasSwitch(switches::kGearsInRenderer)) {
+        if (browser_command_line.HasSwitch(switches::kGearsInRenderer)) {
           if (!AddPolicyForGearsInRenderer(policy)) {
             NOTREACHED();
             return false;
@@ -341,9 +337,10 @@ bool BrowserRenderProcessHost::Init() {
           return false;
         }
 
-        result = broker_service->SpawnTarget(renderer_path.c_str(),
-                                             cmd_line.c_str(),
-                                             policy, &target);
+        result =
+            broker_service->SpawnTarget(renderer_path.c_str(),
+                                        cmd_line.command_line_string().c_str(),
+                                        policy, &target);
         policy->Release();
 
         if (desktop)
@@ -465,8 +462,8 @@ void BrowserRenderProcessHost::InitVisitedLinks() {
 }
 
 void BrowserRenderProcessHost::InitUserScripts() {
-  CommandLine command_line;
-  if (!command_line.HasSwitch(switches::kEnableUserScripts)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableUserScripts)) {
     return;
   }
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_database.cc b/chrome/browser/safe_browsing/safe_browsing_database.cc
index fc3254d..174c867 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database.cc
@@ -20,8 +20,10 @@ static const wchar_t kBloomFilterFile[] = L" Filter";
 
 // Factory method.
 SafeBrowsingDatabase* SafeBrowsingDatabase::Create() {
-  if (CommandLine().HasSwitch(switches::kUseOldSafeBrowsing))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kUseOldSafeBrowsing)) {
     return new SafeBrowsingDatabaseImpl;
+  }
   return new SafeBrowsingDatabaseBloom;
 }
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
index 9e3f5e7..62910c5 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
@@ -909,7 +909,8 @@ TEST(SafeBrowsingDatabase, HashCaching) {
 
   // Test receiving a full add chunk. The old implementation doesn't support
   // this test, so we bail here.
-  if (CommandLine().HasSwitch(switches::kUseOldSafeBrowsing)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kUseOldSafeBrowsing)) {
     TearDownTestDatabase(database);
     return;
   }
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.cc b/chrome/browser/safe_browsing/safe_browsing_service.cc
index 60da2b5..14f31bc 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service.cc
@@ -36,7 +36,8 @@ SafeBrowsingService::SafeBrowsingService()
       resetting_(false),
       database_loaded_(false),
       update_in_progress_(false) {
-  new_safe_browsing_ = !CommandLine().HasSwitch(switches::kUseOldSafeBrowsing);
+  new_safe_browsing_ = !CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUseOldSafeBrowsing);
   base::SystemMonitor* monitor = base::SystemMonitor::Get();
   DCHECK(monitor);
   if (monitor)
diff --git a/chrome/browser/search_engines/template_url_prepopulate_data.cc b/chrome/browser/search_engines/template_url_prepopulate_data.cc
index 826787b..a8d242b 100644
--- a/chrome/browser/search_engines/template_url_prepopulate_data.cc
+++ b/chrome/browser/search_engines/template_url_prepopulate_data.cc
@@ -2680,9 +2680,8 @@ LONG GetCurrentGeoID() {
 
 int GetGeoIDFromPrefs(PrefService* prefs) {
   // See if the user overrode the GeoID on the command line.
-  CommandLine parsed_command_line;
   const std::wstring geoID(
-      parsed_command_line.GetSwitchValue(switches::kGeoID));
+    CommandLine::ForCurrentProcess()->GetSwitchValue(switches::kGeoID));
   if (!geoID.empty())
     return _wtoi(geoID.c_str());
 
diff --git a/chrome/browser/sessions/session_restore_uitest.cc b/chrome/browser/sessions/session_restore_uitest.cc
index 85bb5fd..ae8803e 100644
--- a/chrome/browser/sessions/session_restore_uitest.cc
+++ b/chrome/browser/sessions/session_restore_uitest.cc
@@ -38,8 +38,7 @@ class SessionRestoreUITest : public UITest {
 
     clear_profile_ = false;
 
-    CommandLine::AppendSwitch(&launch_arguments_,
-                              switches::kRestoreLastSession);
+    launch_arguments_.AppendSwitch(switches::kRestoreLastSession);
     UITest::SetUp();
   }
 
@@ -283,7 +282,7 @@ TEST_F(SessionRestoreUITest, DISABLED_DontRestoreWhileIncognito) {
   include_testing_id_ = false;
   use_existing_browser_ = true;
   clear_profile_ = false;
-  CommandLine::AppendSwitch(&launch_arguments_, switches::kRestoreLastSession);
+  launch_arguments_.AppendSwitch(switches::kRestoreLastSession);
   LaunchBrowser(launch_arguments_, false);
 
   // A new window should appear;
@@ -345,9 +344,9 @@ TEST_F(SessionRestoreUITest,
   include_testing_id_ = false;
   use_existing_browser_ = true;
   clear_profile_ = false;
-  std::wstring app_launch_arguments = launch_arguments_;
-  CommandLine::AppendSwitchWithValue(
-      &app_launch_arguments, switches::kApp, UTF8ToWide(url2.spec()));
+  CommandLine app_launch_arguments = launch_arguments_;
+  app_launch_arguments.AppendSwitchWithValue(switches::kApp,
+                                             UTF8ToWide(url2.spec()));
   LaunchBrowser(app_launch_arguments, false);
   int window_count;
   ASSERT_TRUE(automation()->WaitForWindowCountToChange(1, &window_count,
@@ -358,9 +357,8 @@ TEST_F(SessionRestoreUITest,
   CloseWindow(0, 2);
 
   // Restore it, which should bring back the first window with url1.
-  std::wstring restore_launch_arguments = launch_arguments_;
-  CommandLine::AppendSwitch(&restore_launch_arguments,
-                            switches::kRestoreLastSession);
+  CommandLine restore_launch_arguments = launch_arguments_;
+  restore_launch_arguments.AppendSwitch(switches::kRestoreLastSession);
   LaunchBrowser(restore_launch_arguments, false);
   ASSERT_TRUE(automation()->WaitForWindowCountToChange(1, &window_count,
                                                        action_timeout_ms()));
diff --git a/chrome/browser/tab_contents/web_contents.cc b/chrome/browser/tab_contents/web_contents.cc
index c73fc2e..9062894 100644
--- a/chrome/browser/tab_contents/web_contents.cc
+++ b/chrome/browser/tab_contents/web_contents.cc
@@ -1218,7 +1218,7 @@ WebPreferences WebContents::GetWebkitPrefs() {
       prefs->GetBoolean(prefs::kWebKitShrinksStandaloneImagesToFit);
 
   {  // Command line switches are used for preferences with no user interface.
-    CommandLine command_line;
+    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
     web_prefs.developer_extras_enabled =
         !command_line.HasSwitch(switches::kDisableDevTools) &&
         prefs->GetBoolean(prefs::kWebKitDeveloperExtrasEnabled);
diff --git a/chrome/browser/unload_uitest.cc b/chrome/browser/unload_uitest.cc
index 471a3e8..3089e82 100644
--- a/chrome/browser/unload_uitest.cc
+++ b/chrome/browser/unload_uitest.cc
@@ -153,7 +153,7 @@ class UnloadTest : public UITest {
 // we don't get confused and think we're closing the tab.
 TEST_F(UnloadTest, CrossSiteInfiniteUnloadAsync) {
   // Tests makes no sense in single-process mode since the renderer is hung.
-  if (CommandLine().HasSwitch(switches::kSingleProcess))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return;
 
   NavigateToDataURL(INFINITE_UNLOAD_HTML, L"infiniteunload");
@@ -167,7 +167,7 @@ TEST_F(UnloadTest, CrossSiteInfiniteUnloadAsync) {
 // we correctly nav to each one. 
 TEST_F(UnloadTest, CrossSiteInfiniteUnloadSync) {
   // Tests makes no sense in single-process mode since the renderer is hung.
-  if (CommandLine().HasSwitch(switches::kSingleProcess))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return;
 
   NavigateToDataURL(INFINITE_UNLOAD_HTML, L"infiniteunload");
@@ -181,7 +181,7 @@ TEST_F(UnloadTest, CrossSiteInfiniteUnloadSync) {
 // we don't get confused and think we're closing the tab.
 TEST_F(UnloadTest, CrossSiteInfiniteBeforeUnloadAsync) {
   // Tests makes no sense in single-process mode since the renderer is hung.
-  if (CommandLine().HasSwitch(switches::kSingleProcess))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return;
 
   NavigateToDataURL(INFINITE_BEFORE_UNLOAD_HTML, L"infinitebeforeunload");
@@ -195,7 +195,7 @@ TEST_F(UnloadTest, CrossSiteInfiniteBeforeUnloadAsync) {
 // we correctly nav to each one. 
 TEST_F(UnloadTest, CrossSiteInfiniteBeforeUnloadSync) {
   // Tests makes no sense in single-process mode since the renderer is hung.
-  if (CommandLine().HasSwitch(switches::kSingleProcess))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return;
 
   NavigateToDataURL(INFINITE_BEFORE_UNLOAD_HTML, L"infinitebeforeunload");
diff --git a/chrome/browser/user_data_manager.cc b/chrome/browser/user_data_manager.cc
index 3353016..554c53f 100644
--- a/chrome/browser/user_data_manager.cc
+++ b/chrome/browser/user_data_manager.cc
@@ -177,15 +177,14 @@ std::wstring UserDataManager::GetCommandForProfile(
   std::wstring user_data_dir = GetUserDataFolderForProfile(profile_name);
   std::wstring command;
   PathService::Get(base::FILE_EXE, &command);
-  CommandLine::AppendSwitchWithValue(&command,
-                                     switches::kUserDataDir,
+  CommandLine command_line(command);
+  command_line.AppendSwitchWithValue(switches::kUserDataDir,
                                      user_data_dir);
   std::wstring local_state_path;
   PathService::Get(chrome::FILE_LOCAL_STATE, &local_state_path);
-  CommandLine::AppendSwitchWithValue(&command,
-                                     switches::kParentProfile,
+  command_line.AppendSwitchWithValue(switches::kParentProfile,
                                      local_state_path);
-  return command;
+  return command_line.command_line_string();
 }
 
 void UserDataManager::LaunchChromeForProfile(
diff --git a/chrome/browser/views/frame/browser_view.cc b/chrome/browser/views/frame/browser_view.cc
index 7bf7156e..6dae951 100644
--- a/chrome/browser/views/frame/browser_view.cc
+++ b/chrome/browser/views/frame/browser_view.cc
@@ -327,8 +327,10 @@ void BrowserView::Init() {
 
   // Start a hung plugin window detector for this browser object (as long as
   // hang detection is not disabled).
-  if (!CommandLine().HasSwitch(switches::kDisableHangMonitor))
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableHangMonitor)) {
     InitHangMonitor();
+  }
 
   LoadAccelerators();
   SetAccessibleName(l10n_util::GetString(IDS_PRODUCT_NAME));
diff --git a/chrome/common/child_process.cc b/chrome/common/child_process.cc
index 112fceb..b64984c 100644
--- a/chrome/common/child_process.cc
+++ b/chrome/common/child_process.cc
@@ -77,7 +77,7 @@ bool ChildProcess::GlobalInit(const std::wstring &channel_name,
 
   child_process_ = factory->Create(channel_name);
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kUserAgent)) {
 #if defined(OS_WIN)
     // TODO(port): calling this connects an, otherwise disconnected, subgraph
diff --git a/chrome/common/chrome_paths.cc b/chrome/common/chrome_paths.cc
index 297b963..e842cbc 100644
--- a/chrome/common/chrome_paths.cc
+++ b/chrome/common/chrome_paths.cc
@@ -49,8 +49,8 @@ bool GetDefaultUserDataDirectory(std::wstring* result) {
 bool GetGearsPluginPathFromCommandLine(std::wstring *path) {
 #ifndef NDEBUG
   // for debugging, support a cmd line based override
-  CommandLine command_line;
-  *path = command_line.GetSwitchValue(switches::kGearsPluginPathOverride);
+  *path = CommandLine::ForCurrentProcess()->GetSwitchValue(
+              switches::kGearsPluginPathOverride);
   return !path->empty();
 #else
   return false;
diff --git a/chrome/common/chrome_plugin_lib.cc b/chrome/common/chrome_plugin_lib.cc
index 4af7a558..1587a2d 100644
--- a/chrome/common/chrome_plugin_lib.cc
+++ b/chrome/common/chrome_plugin_lib.cc
@@ -44,8 +44,7 @@ CPError STDCALL Gears_CP_Initialize(CPID id, const CPBrowserFuncs *bfuncs,
 
 static bool IsSingleProcessMode() {
   // We don't support ChromePlugins in single-process mode.
-  CommandLine command_line;
-  return command_line.HasSwitch(switches::kSingleProcess);
+  return CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess);
 }
 
 // static
diff --git a/chrome/common/chrome_plugin_util.cc b/chrome/common/chrome_plugin_util.cc
index 56b1f54..610c0b9 100644
--- a/chrome/common/chrome_plugin_util.cc
+++ b/chrome/common/chrome_plugin_util.cc
@@ -121,7 +121,7 @@ int PluginResponseUtils::GetResponseInfo(
 
 CPError CPB_GetCommandLineArgumentsCommon(const char* url,
                                           std::string* arguments) {
-  CommandLine cmd;
+  const CommandLine cmd = *CommandLine::ForCurrentProcess();
   std::wstring arguments_w;
 
   // Use the same UserDataDir for new launches that we currently have set.
@@ -131,8 +131,8 @@ CPError CPB_GetCommandLineArgumentsCommon(const char* url,
     wchar_t user_data_dir_full[MAX_PATH];
     if (_wfullpath(user_data_dir_full, user_data_dir.c_str(), MAX_PATH) &&
         file_util::PathExists(user_data_dir_full)) {
-      CommandLine::AppendSwitchWithValue(
-          &arguments_w, switches::kUserDataDir, user_data_dir_full);
+      arguments_w += std::wstring(L"--") + switches::kUserDataDir +
+                     L'=' + user_data_dir_full;
     }
   }
 
@@ -140,7 +140,7 @@ CPError CPB_GetCommandLineArgumentsCommon(const char* url,
   // chrome.
   // Note: Do not change this flag!  Old Gears shortcuts will break if you do!
   std::wstring url_w = UTF8ToWide(url);
-  CommandLine::AppendSwitchWithValue(&arguments_w, switches::kApp, url_w);
+  arguments_w += std::wstring(L"--") + switches::kApp + L'=' + url_w;
 
   *arguments = WideToUTF8(arguments_w);
 
diff --git a/chrome/common/common_glue.cc b/chrome/common/common_glue.cc
index 6c33f1e..7d32310 100644
--- a/chrome/common/common_glue.cc
+++ b/chrome/common/common_glue.cc
@@ -29,7 +29,7 @@ std::wstring GetWebKitLocale() {
   // The browser process should have passed the locale to the renderer via the
   // --lang command line flag.  In single process mode, this will return the
   // wrong value.  TODO(tc): Fix this for single process mode.
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   const std::wstring& lang =
       parsed_command_line.GetSwitchValue(switches::kLang);
   DCHECK(!lang.empty() ||
diff --git a/chrome/common/debug_flags.cc b/chrome/common/debug_flags.cc
index 1e10b78..9f62cbe 100644
--- a/chrome/common/debug_flags.cc
+++ b/chrome/common/debug_flags.cc
@@ -8,11 +8,11 @@
 #include "base/command_line.h"
 #include "chrome/common/chrome_switches.h"
 
-bool DebugFlags::ProcessDebugFlags(std::wstring* command_line,
+bool DebugFlags::ProcessDebugFlags(CommandLine* command_line,
                                    ChildProcessType type,
                                    bool is_in_sandbox) {
   bool should_help_child = false;
-  CommandLine current_cmd_line;
+  const CommandLine& current_cmd_line = *CommandLine::ForCurrentProcess();
   if (current_cmd_line.HasSwitch(switches::kDebugChildren)) {
     // Look to pass-on the kDebugOnStart flag.
     std::wstring value;
@@ -20,12 +20,10 @@ bool DebugFlags::ProcessDebugFlags(std::wstring* command_line,
     if (value.empty() ||
         (type == RENDERER && value == switches::kRendererProcess) ||
         (type == PLUGIN && value == switches::kPluginProcess)) {
-      CommandLine::AppendSwitch(command_line, switches::kDebugOnStart);
+      command_line->AppendSwitch(switches::kDebugOnStart);
       should_help_child = true;
     }
-    CommandLine::AppendSwitchWithValue(command_line,
-                                       switches::kDebugChildren,
-                                       value);
+    command_line->AppendSwitchWithValue(switches::kDebugChildren, value);
   } else if (current_cmd_line.HasSwitch(switches::kWaitForDebuggerChildren)) {
     // Look to pass-on the kWaitForDebugger flag.
     std::wstring value;
@@ -33,11 +31,10 @@ bool DebugFlags::ProcessDebugFlags(std::wstring* command_line,
     if (value.empty() ||
         (type == RENDERER && value == switches::kRendererProcess) ||
         (type == PLUGIN && value == switches::kPluginProcess)) {
-      CommandLine::AppendSwitch(command_line, switches::kWaitForDebugger);
+      command_line->AppendSwitch(switches::kWaitForDebugger);
     }
-    CommandLine::AppendSwitchWithValue(command_line,
-                                       switches::kWaitForDebuggerChildren,
-                                       value);
+    command_line->AppendSwitchWithValue(switches::kWaitForDebuggerChildren,
+                                        value);
   }
   return should_help_child;
 }
diff --git a/chrome/common/debug_flags.h b/chrome/common/debug_flags.h
index 9d4ebba..c2115a9 100644
--- a/chrome/common/debug_flags.h
+++ b/chrome/common/debug_flags.h
@@ -5,7 +5,7 @@
 #ifndef CHROME_COMMON_DEBUG_FLAGS_H__
 #define CHROME_COMMON_DEBUG_FLAGS_H__
 
-#include <string>
+class CommandLine;
 
 class DebugFlags {
  public:
@@ -15,13 +15,15 @@ class DebugFlags {
     UNKNOWN
   };
 
-  // Updates the command line arguments with debug-related flags. If debug flags
-  // have been used with this process, they will be filtered and added to
-  // command_line as needed. is_in_sandbox must be true if the child process will
-  // be in a sandbox.
-  // Returns true if the caller should "help" the child process by calling the JIT
-  // debugger on it. It may only happen if is_in_sandbox is true.
-  static bool ProcessDebugFlags(std::wstring* command_line,
+  // Updates the command line arguments with debug-related flags. If
+  // debug flags have been used with this process, they will be
+  // filtered and added to command_line as needed. is_in_sandbox must
+  // be true if the child process will be in a sandbox.
+  //
+  // Returns true if the caller should "help" the child process by
+  // calling the JIT debugger on it. It may only happen if
+  // is_in_sandbox is true.
+  static bool ProcessDebugFlags(CommandLine* command_line,
                                 ChildProcessType type,
                                 bool is_in_sandbox);
 };
diff --git a/chrome/common/ipc_channel_posix.cc b/chrome/common/ipc_channel_posix.cc
index 57d30bf..6c6f17c 100644
--- a/chrome/common/ipc_channel_posix.cc
+++ b/chrome/common/ipc_channel_posix.cc
@@ -244,7 +244,8 @@ Channel::ChannelImpl::ChannelImpl(const std::wstring& channel_id, Mode mode,
     : mode_(mode),
       is_blocked_on_write_(false),
       message_send_bytes_written_(0),
-      uses_fifo_(CommandLine().HasSwitch(switches::kTestingChannelID)),
+      uses_fifo_(CommandLine::ForCurrentProcess()->HasSwitch(
+                     switches::kTestingChannelID)),
       server_listen_pipe_(-1),
       pipe_(-1),
       client_pipe_(-1),
diff --git a/chrome/common/ipc_logging.cc b/chrome/common/ipc_logging.cc
index db8bf84..ec2fe82 100644
--- a/chrome/common/ipc_logging.cc
+++ b/chrome/common/ipc_logging.cc
@@ -45,7 +45,7 @@ Logging::Logging()
   // enabled, so child processes can know when logging is enabled.
   int browser_pid;
 
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   std::wstring process_type =
     parsed_command_line.GetSwitchValue(switches::kProcessType);
   if (process_type.empty()) {
diff --git a/chrome/common/ipc_tests.cc b/chrome/common/ipc_tests.cc
index be3b0d9..b0add18 100644
--- a/chrome/common/ipc_tests.cc
+++ b/chrome/common/ipc_tests.cc
@@ -52,7 +52,8 @@ void IPCChannelTest::TearDown() {
 base::ProcessHandle IPCChannelTest::SpawnChild(ChildType child_type,
                                                IPC::Channel *channel) {
   // kDebugChildren support.
-  bool debug_on_start = CommandLine().HasSwitch(switches::kDebugChildren);
+  bool debug_on_start =
+      CommandLine::ForCurrentProcess()->HasSwitch(switches::kDebugChildren);
 
   switch (child_type) {
   case TEST_CLIENT:
@@ -73,7 +74,8 @@ base::ProcessHandle IPCChannelTest::SpawnChild(ChildType child_type,
 base::ProcessHandle IPCChannelTest::SpawnChild(ChildType child_type,
                                                IPC::Channel *channel) {
   // kDebugChildren support.
-  bool debug_on_start = CommandLine().HasSwitch(switches::kDebugChildren);
+  bool debug_on_start =
+      CommandLine::ForCurrentProcess()->HasSwitch(switches::kDebugChildren);
 
   base::file_handle_mapping_vector fds_to_map;
   int src_fd;
@@ -225,9 +227,10 @@ TEST_F(IPCChannelTest, ChannelProxyTest) {
     channel_listener.Init(&chan);
 
 #if defined(OS_WIN)
-  base::ProcessHandle process_handle = SpawnChild(TEST_CLIENT, NULL);
+    base::ProcessHandle process_handle = SpawnChild(TEST_CLIENT, NULL);
 #elif defined(OS_POSIX)
-    bool debug_on_start = CommandLine().HasSwitch(switches::kDebugChildren);
+    bool debug_on_start = CommandLine::ForCurrentProcess()->HasSwitch(
+                              switches::kDebugChildren);
     base::file_handle_mapping_vector fds_to_map;
     int src_fd;
     int dest_fd;
diff --git a/chrome/common/l10n_util.cc b/chrome/common/l10n_util.cc
index d9fb299..86a36eb 100644
--- a/chrome/common/l10n_util.cc
+++ b/chrome/common/l10n_util.cc
@@ -261,7 +261,7 @@ std::wstring GetApplicationLocale(const std::wstring& pref_locale) {
   std::wstring resolved_locale;
 
   // First, check to see if there's a --lang flag.
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   const std::wstring& lang_arg =
       parsed_command_line.GetSwitchValue(switches::kLang);
   if (!lang_arg.empty()) {
diff --git a/chrome/common/logging_chrome_uitest.cc b/chrome/common/logging_chrome_uitest.cc
index f1a121c..b88deb6 100644
--- a/chrome/common/logging_chrome_uitest.cc
+++ b/chrome/common/logging_chrome_uitest.cc
@@ -72,8 +72,7 @@ class AssertionTest : public UITest {
     // We're testing the renderer rather than the browser assertion here,
     // because the browser assertion would flunk the test during SetUp()
     // (since TAU wouldn't be able to find the browser window).
-    CommandLine::AppendSwitch(&launch_arguments_,
-                              switches::kRendererAssertTest);
+    launch_arguments_.AppendSwitch(switches::kRendererAssertTest);
   }
 };
 
@@ -98,8 +97,7 @@ class RendererCrashTest : public UITest {
     // Initial loads will never complete due to crash.
     wait_for_initial_loads_ = false;
 
-    CommandLine::AppendSwitch(&launch_arguments_,
-                              switches::kRendererCrashTest);
+    launch_arguments_.AppendSwitch(switches::kRendererCrashTest);
   }
 };
 
@@ -123,8 +121,7 @@ class BrowserCrashTest : public UITest {
     // Initial loads will never complete due to crash.
     wait_for_initial_loads_ = false;
 
-    CommandLine::AppendSwitch(&launch_arguments_,
-                              switches::kBrowserCrashTest);
+    launch_arguments_.AppendSwitch(switches::kBrowserCrashTest);
   }
 };
 
diff --git a/chrome/common/main_function_params.h b/chrome/common/main_function_params.h
index b8156ae..e3a1c55 100644
--- a/chrome/common/main_function_params.h
+++ b/chrome/common/main_function_params.h
@@ -12,12 +12,10 @@
 #include "base/command_line.h"
 #include "chrome/common/sandbox_init_wrapper.h"
 
-// TODO(pinkerton): |cl| should be const, but can't be due to bug 6144.
-
 struct MainFunctionParams {
-  MainFunctionParams(CommandLine& cl, const SandboxInitWrapper& sb)
+  MainFunctionParams(const CommandLine& cl, const SandboxInitWrapper& sb)
       : command_line_(cl), sandbox_info_(sb) { }
-  CommandLine& command_line_;
+  const CommandLine& command_line_;
   const SandboxInitWrapper& sandbox_info_;
 };
 
diff --git a/chrome/common/pref_service_uitest.cc b/chrome/common/pref_service_uitest.cc
index 0ecd114..4ffd4e7 100644
--- a/chrome/common/pref_service_uitest.cc
+++ b/chrome/common/pref_service_uitest.cc
@@ -43,9 +43,8 @@ public:
     ASSERT_TRUE(::SetFileAttributesW(tmp_pref_file_.c_str(),
         FILE_ATTRIBUTE_NORMAL));
 
-    CommandLine::AppendSwitchWithValue(&launch_arguments_,
-                                       switches::kUserDataDir,
-                                       tmp_profile_);
+    launch_arguments_.AppendSwitchWithValue(switches::kUserDataDir,
+                                            tmp_profile_);
   }
 
   bool LaunchAppWithProfile() {
diff --git a/chrome/common/temp_scaffolding_stubs.cpp b/chrome/common/temp_scaffolding_stubs.cpp
index 756c8c2..af74d6d 100644
--- a/chrome/common/temp_scaffolding_stubs.cpp
+++ b/chrome/common/temp_scaffolding_stubs.cpp
@@ -14,7 +14,7 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/pref_service.h"
 
-BrowserProcessImpl::BrowserProcessImpl(CommandLine& command_line)
+BrowserProcessImpl::BrowserProcessImpl(const CommandLine& command_line)
     : created_local_state_(), created_metrics_service_(),
       created_profile_manager_() {
   g_browser_process = this;
diff --git a/chrome/common/temp_scaffolding_stubs.h b/chrome/common/temp_scaffolding_stubs.h
index f7f2bbb..603e7ca 100644
--- a/chrome/common/temp_scaffolding_stubs.h
+++ b/chrome/common/temp_scaffolding_stubs.h
@@ -83,7 +83,7 @@ class GoogleUpdateSettings {
 
 class BrowserProcessImpl : public BrowserProcess {
  public:
-  BrowserProcessImpl(CommandLine& command_line);
+  BrowserProcessImpl(const CommandLine& command_line);
   virtual ~BrowserProcessImpl();
 
   virtual void EndSession() { }
@@ -126,7 +126,7 @@ class BrowserProcessImpl : public BrowserProcess {
 
 class FirstRunBrowserProcess : public BrowserProcessImpl {
  public:
-  FirstRunBrowserProcess(CommandLine& command_line)
+  FirstRunBrowserProcess(const CommandLine& command_line)
       : BrowserProcessImpl(command_line) {
   }
   virtual ~FirstRunBrowserProcess() { }
diff --git a/chrome/installer/setup/main.cc b/chrome/installer/setup/main.cc
index e888f0b..8f57e06 100755
--- a/chrome/installer/setup/main.cc
+++ b/chrome/installer/setup/main.cc
@@ -457,7 +457,8 @@ int WINAPI wWinMain(HINSTANCE instance, HINSTANCE prev_instance,
                     wchar_t* command_line, int show_command) {
   // The exit manager is in charge of calling the dtors of singletons.
   base::AtExitManager exit_manager;
-  CommandLine parsed_command_line;
+  CommandLine::Init(0, NULL);
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   installer::InitInstallerLogging(parsed_command_line);
   int options = GetInstallOptions(parsed_command_line);
   if (options & installer_util::VERBOSE_LOGGING)
diff --git a/chrome/installer/setup/setup.cc b/chrome/installer/setup/setup.cc
index 27475242..0fe3afb 100755
--- a/chrome/installer/setup/setup.cc
+++ b/chrome/installer/setup/setup.cc
@@ -51,7 +51,6 @@ void DoFirstInstallTasks(std::wstring install_path, int options) {
   // will work only if current user has admin rights.
   std::wstring chrome_exe(install_path);
   file_util::AppendToPath(&chrome_exe, installer_util::kChromeExe);
-  CommandLine cmd_line;
   LOG(INFO) << "Registering Chrome as browser";
   ShellUtil::RegisterStatus ret = ShellUtil::FAILURE;
   if (options & installer_util::MAKE_CHROME_DEFAULT) {
diff --git a/chrome/plugin/plugin_main.cc b/chrome/plugin/plugin_main.cc
index ac9fd90..e2416f0 100644
--- a/chrome/plugin/plugin_main.cc
+++ b/chrome/plugin/plugin_main.cc
@@ -16,7 +16,7 @@
 
 // mainline routine for running as the plugin process
 int PluginMain(const MainFunctionParams& parameters) {
-  CommandLine& parsed_command_line = parameters.command_line_;
+  const CommandLine& parsed_command_line = parameters.command_line_;
   sandbox::TargetServices* target_services = 
       parameters.sandbox_info_.TargetServices();
 
diff --git a/chrome/plugin/webplugin_delegate_stub.cc b/chrome/plugin/webplugin_delegate_stub.cc
index 28c0e63..31444b6 100644
--- a/chrome/plugin/webplugin_delegate_stub.cc
+++ b/chrome/plugin/webplugin_delegate_stub.cc
@@ -123,7 +123,7 @@ void WebPluginDelegateStub::OnInit(const PluginMsg_Init_Params& params,
     argv[i] = const_cast<char*>(params.arg_values[i].c_str());
   }
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   FilePath path =
       FilePath(command_line.GetSwitchValue(switches::kPluginPath));
   delegate_ = WebPluginDelegateImpl::Create(
diff --git a/chrome/renderer/render_process.cc b/chrome/renderer/render_process.cc
index b2b4606..2fe1af7 100644
--- a/chrome/renderer/render_process.cc
+++ b/chrome/renderer/render_process.cc
@@ -63,7 +63,7 @@ bool RenderProcess::GlobalInit(const std::wstring &channel_name) {
     }
   }
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kJavaScriptFlags)) {
     webkit_glue::SetJavaScriptFlags(
       command_line.GetSwitchValue(switches::kJavaScriptFlags));
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index 9927171..8f08add 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -289,7 +289,7 @@ void RenderView::Init(HWND parent_hwnd,
   host_window_ = parent_hwnd;
   modal_dialog_event_.reset(modal_dialog_event);
 
-  CommandLine command_line;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   enable_dom_automation_ =
       command_line.HasSwitch(switches::kDomAutomationController);
   disable_popup_blocking_ =
@@ -1834,8 +1834,8 @@ static bool ShouldLoadPluginInProcess(const std::string& mime_type,
 
   if (mime_type == "application/x-googlegears") {
     *is_gears = true;
-    CommandLine cmd;
-    return cmd.HasSwitch(switches::kGearsInRenderer);
+    return CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kGearsInRenderer);
   }
 
   return false;
diff --git a/chrome/renderer/renderer_glue.cc b/chrome/renderer/renderer_glue.cc
index 7516ace..3bc7c63 100644
--- a/chrome/renderer/renderer_glue.cc
+++ b/chrome/renderer/renderer_glue.cc
@@ -136,7 +136,7 @@ ScopedClipboardWriterGlue::~ScopedClipboardWriterGlue() {
 namespace webkit_glue {
 
 bool IsMediaPlayerAvailable() {
-  return CommandLine().HasSwitch(switches::kEnableVideo);
+  return CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableVideo);
 }
 
 void PrefetchDns(const std::string& hostname) {
diff --git a/chrome/renderer/renderer_main.cc b/chrome/renderer/renderer_main.cc
index 476e4f7..b3d9fec 100644
--- a/chrome/renderer/renderer_main.cc
+++ b/chrome/renderer/renderer_main.cc
@@ -46,7 +46,7 @@ static void HandleRendererErrorTestParameters(const CommandLine& command_line) {
 
 // mainline routine for running as the Rendererer process
 int RendererMain(const MainFunctionParams& parameters) {
-  CommandLine& parsed_command_line = parameters.command_line_;
+  const CommandLine& parsed_command_line = parameters.command_line_;
   sandbox::TargetServices* target_services = 
       parameters.sandbox_info_.TargetServices();
 
diff --git a/chrome/test/automated_ui_tests/automated_ui_tests.cc b/chrome/test/automated_ui_tests/automated_ui_tests.cc
index dcbac5b..81d0f0b 100644
--- a/chrome/test/automated_ui_tests/automated_ui_tests.cc
+++ b/chrome/test/automated_ui_tests/automated_ui_tests.cc
@@ -79,7 +79,7 @@ AutomatedUITest::AutomatedUITest()
       post_action_delay_(0) {
   show_window_ = true;
   GetSystemTimeAsFileTime(&test_start_time_);
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kDebugModeSwitch))
     debug_logging_enabled_ = true;
   if (parsed_command_line.HasSwitch(kWaitSwitch)) {
@@ -95,7 +95,7 @@ AutomatedUITest::AutomatedUITest()
 AutomatedUITest::~AutomatedUITest() {}
 
 void AutomatedUITest::RunReproduction() {
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   xml_writer_.StartWriting();
   xml_writer_.StartElement("Report");
   std::string action_string =
@@ -863,7 +863,7 @@ bool AutomatedUITest::SimulateKeyPressInActiveWindow(wchar_t key, int flags) {
 
 bool AutomatedUITest::InitXMLReader() {
   std::wstring input_path;
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kInputFilePathSwitch))
     input_path = parsed_command_line.GetSwitchValue(kInputFilePathSwitch);
   else
@@ -877,7 +877,7 @@ bool AutomatedUITest::InitXMLReader() {
 bool AutomatedUITest::WriteReportToFile() {
   std::ofstream error_file;
   std::wstring path;
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kOutputFilePathSwitch))
     path = parsed_command_line.GetSwitchValue(kOutputFilePathSwitch);
   else
@@ -897,7 +897,7 @@ bool AutomatedUITest::WriteReportToFile() {
 void AutomatedUITest::AppendToOutputFile(const std::string &append_string) {
   std::ofstream error_file;
   std::wstring path;
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kOutputFilePathSwitch))
     path = parsed_command_line.GetSwitchValue(kOutputFilePathSwitch);
   else
@@ -1001,7 +1001,7 @@ bool AutomatedUITest::DidCrash(bool update_total_crashes) {
 }
 
 TEST_F(AutomatedUITest, TheOneAndOnlyTest) {
-  CommandLine parsed_command_line;
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kReproSwitch))
     RunReproduction();
   else
diff --git a/chrome/test/automation/automation_proxy_uitest.cc b/chrome/test/automation/automation_proxy_uitest.cc
index 33c6a30..add33f4 100644
--- a/chrome/test/automation/automation_proxy_uitest.cc
+++ b/chrome/test/automation/automation_proxy_uitest.cc
@@ -25,9 +25,8 @@ class AutomationProxyTest : public UITest {
  protected:
   AutomationProxyTest() {
     dom_automation_enabled_ = true;
-    CommandLine::AppendSwitchWithValue(&launch_arguments_,
-                                       switches::kLang,
-                                       L"en-us");
+    launch_arguments_.AppendSwitchWithValue(switches::kLang,
+                                            L"en-us");
   }
 };
 
@@ -371,7 +370,9 @@ class AutomationProxyTest2 : public AutomationProxyVisibleTest {
 
     document2_ = test_data_directory_;
     file_util::AppendToPath(&document2_, L"title2.html");
-    launch_arguments_ = document1_ + L" " + document2_;
+    launch_arguments_ = CommandLine(L"");
+    launch_arguments_.AppendLooseValue(document1_);
+    launch_arguments_.AppendLooseValue(document2_);
   }
 
   std::wstring document1_;
@@ -576,7 +577,8 @@ class AutomationProxyTest3 : public UITest {
     file_util::AppendToPath(&document1_, L"frame_dom_access.html");
 
     dom_automation_enabled_ = true;
-    launch_arguments_ = document1_;
+    launch_arguments_ = CommandLine(L"");
+    launch_arguments_.AppendLooseValue(document1_);
   }
 
   std::wstring document1_;
diff --git a/chrome/test/memory_test/memory_test.cc b/chrome/test/memory_test/memory_test.cc
index 23cb072..2ef79d1 100644
--- a/chrome/test/memory_test/memory_test.cc
+++ b/chrome/test/memory_test/memory_test.cc
@@ -32,17 +32,17 @@ class MemoryTest : public UITest {
 
     // For now, turn off plugins because they crash like crazy.
     // TODO(mbelshe): Fix Chrome to not crash with plugins.
-    CommandLine::AppendSwitch(&launch_arguments_, switches::kDisablePlugins);
+    launch_arguments_.AppendSwitch(switches::kDisablePlugins);
 
-    CommandLine::AppendSwitch(&launch_arguments_, switches::kEnableLogging);
+    launch_arguments_.AppendSwitch(switches::kEnableLogging);
 
     // Use the playback cache, but don't use playback events.
-    CommandLine::AppendSwitch(&launch_arguments_, switches::kPlaybackMode);
-    CommandLine::AppendSwitch(&launch_arguments_, switches::kNoEvents);
+    launch_arguments_.AppendSwitch(switches::kPlaybackMode);
+    launch_arguments_.AppendSwitch(switches::kNoEvents);
 
     // Get the specified user data dir (optional)
     std::wstring profile_dir =
-      CommandLine().GetSwitchValue(switches::kUserDataDir);
+      CommandLine::ForCurrentProcess()->GetSwitchValue(switches::kUserDataDir);
 
     if (profile_dir.length() == 0) {
       // Compute the user-data-dir which contains our test cache.
@@ -63,9 +63,8 @@ class MemoryTest : public UITest {
       }
     }
 
-    CommandLine::AppendSwitchWithValue(&launch_arguments_,
-                                       switches::kUserDataDir,
-                                       user_data_dir_);
+    launch_arguments_.AppendSwitchWithValue(switches::kUserDataDir,
+                                            user_data_dir_);
   }
 
   ~MemoryTest() {
diff --git a/chrome/test/page_cycler/page_cycler_test.cc b/chrome/test/page_cycler/page_cycler_test.cc
index e42cf14..8f5fead 100644
--- a/chrome/test/page_cycler/page_cycler_test.cc
+++ b/chrome/test/page_cycler/page_cycler_test.cc
@@ -38,9 +38,8 @@ class PageCyclerTest : public UITest {
     show_window_ = true;
 
     // Expose garbage collection for the page cycler tests.
-    CommandLine::AppendSwitchWithValue(&launch_arguments_,
-                                       switches::kJavaScriptFlags,
-                                       L"--expose_gc");
+    launch_arguments_.AppendSwitchWithValue(switches::kJavaScriptFlags,
+                                            L"--expose_gc");
   }
 
   // For HTTP tests, the name must be safe for use in a URL without escaping.
diff --git a/chrome/test/plugin/plugin_test.cpp b/chrome/test/plugin/plugin_test.cpp
index d458662..0faaf8e 100644
--- a/chrome/test/plugin/plugin_test.cpp
+++ b/chrome/test/plugin/plugin_test.cpp
@@ -76,27 +76,16 @@ class PluginTest : public UITest {
                       KEY_WRITE)) {
         regkey.CreateKey(L"CHROME.EXE", KEY_READ);
       }
-      if (!launch_arguments_.empty())
-        launch_arguments_.append(L" ");
-      launch_arguments_.append(L"--" kNoNativeActiveXShimSwitch);
+      launch_arguments_.AppendSwitch(kNoNativeActiveXShimSwitch);
 
     } else if (strcmp(test_info->name(), "MediaPlayerOld") == 0) {
       // When testing the old WMP plugin, we need to force Chrome to not load
       // the new plugin.
-      if (!launch_arguments_.empty())
-        launch_arguments_.append(L" ");
-
-      launch_arguments_.append(L"--" kUseOldWMPPluginSwitch);
-      launch_arguments_.append(L" ");
-      launch_arguments_.append(L"--" kNoNativeActiveXShimSwitch);
+      launch_arguments_.AppendSwitch(kUseOldWMPPluginSwitch);
+      launch_arguments_.AppendSwitch(kNoNativeActiveXShimSwitch);
     } else if (strcmp(test_info->name(), "FlashSecurity") == 0) {
-      if (!launch_arguments_.empty())
-        launch_arguments_.append(L" ");
-
-      launch_arguments_.append(L"--");
-      launch_arguments_.append(switches::kTestSandbox); 
-      launch_arguments_.append(L"=");
-      launch_arguments_.append(L"security_tests.dll");
+      launch_arguments_.AppendSwitchWithValue(switches::kTestSandbox,
+                                              L"security_tests.dll");
     }
 
     UITest::SetUp();
diff --git a/chrome/test/reliability/reliability_test_suite.h b/chrome/test/reliability/reliability_test_suite.h
index 6170d63..809ca52 100644
--- a/chrome/test/reliability/reliability_test_suite.h
+++ b/chrome/test/reliability/reliability_test_suite.h
@@ -18,7 +18,7 @@ protected:
   virtual void Initialize() {
     UITestSuite::Initialize();
 
-    SetPageRange(CommandLine());
+    SetPageRange(CommandLine(L""));
   }
 };
 
diff --git a/chrome/test/startup/startup_test.cc b/chrome/test/startup/startup_test.cc
index 34f91b9..70b54de 100644
--- a/chrome/test/startup/startup_test.cc
+++ b/chrome/test/startup/startup_test.cc
@@ -110,7 +110,7 @@ class StartupFileTest : public StartupTest {
     ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &file_url));
     file_util::AppendToPath(&file_url, L"empty.html");
     ASSERT_TRUE(file_util::PathExists(file_url));
-    launch_arguments_ += file_url;
+    launch_arguments_.AppendLooseValue(file_url);
 
     pages_ = WideToUTF8(file_url);
   }
diff --git a/chrome/test/ui/inspector_controller_uitest.cc b/chrome/test/ui/inspector_controller_uitest.cc
index 29b1489..289cca0 100644
--- a/chrome/test/ui/inspector_controller_uitest.cc
+++ b/chrome/test/ui/inspector_controller_uitest.cc
@@ -34,7 +34,7 @@ TEST_F(InspectorControllerTest, DISABLED_InspectElement) {
   if (IsTestCaseDisabled())
     return;
 
-  if (CommandLine().HasSwitch(switches::kSingleProcess))
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return;
 
   scoped_refptr<HTTPTestServer> server =
diff --git a/chrome/test/ui/omnibox_uitest.cc b/chrome/test/ui/omnibox_uitest.cc
index 83e14fd..7b317af 100644
--- a/chrome/test/ui/omnibox_uitest.cc
+++ b/chrome/test/ui/omnibox_uitest.cc
@@ -133,7 +133,8 @@ void OmniboxTest::RunQueryChain(const std::wstring& input_text) {
 // </omnibox_tests>
 
 TEST_F(OmniboxTest, Measure) {
-  if (!CommandLine().HasSwitch(kRunOmniboxTest)) return;
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(kRunOmniboxTest))
+    return;
 
   std::wstring omnibox_tests_path;
   PathService::Get(chrome::DIR_TEST_DATA, &omnibox_tests_path);
diff --git a/chrome/test/ui/sandbox_uitests.cc b/chrome/test/ui/sandbox_uitests.cc
index cbfaa65..d898cf5 100644
--- a/chrome/test/ui/sandbox_uitests.cc
+++ b/chrome/test/ui/sandbox_uitests.cc
@@ -14,9 +14,8 @@ class SandboxTest : public UITest {
  protected:
   // Launches chrome with the --test-sandbox=security_tests.dll flag.
   SandboxTest() : UITest() {
-    CommandLine::AppendSwitchWithValue(&launch_arguments_,
-                                       switches::kTestSandbox,
-                                       L"security_tests.dll");
+    launch_arguments_.AppendSwitchWithValue(switches::kTestSandbox,
+                                            L"security_tests.dll");
   }
 };
 
diff --git a/chrome/test/ui/ui_test.cc b/chrome/test/ui/ui_test.cc
index 06591ec..597b0af 100644
--- a/chrome/test/ui/ui_test.cc
+++ b/chrome/test/ui/ui_test.cc
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "chrome/test/ui/ui_test.h"
+
 #include <set>
 #include <vector>
 
-#include "chrome/test/ui/ui_test.h"
-
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
@@ -92,6 +92,7 @@ bool UITest::DieFileDie(const std::wstring& file, bool recurse) {
 
 UITest::UITest()
     : testing::Test(),
+      launch_arguments_(L""),
       expected_errors_(0),
       expected_crashes_(0),
       homepage_(L"about:blank"),
@@ -177,28 +178,29 @@ void UITest::TearDown() {
 
 // Pick up the various test time out values from the command line.
 void UITest::InitializeTimeouts() {
-  if (CommandLine().HasSwitch(kUiTestTimeout)) {
-    std::wstring timeout_str = CommandLine().GetSwitchValue(kUiTestTimeout);
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(kUiTestTimeout)) {
+    std::wstring timeout_str = command_line.GetSwitchValue(kUiTestTimeout);
     int timeout = StringToInt(timeout_str);
     command_execution_timeout_ms_ = std::max(kMaxTestExecutionTime, timeout);
   }
 
-  if (CommandLine().HasSwitch(kUiTestActionTimeout)) {
-    std::wstring act_str = CommandLine().GetSwitchValue(kUiTestActionTimeout);
+  if (command_line.HasSwitch(kUiTestActionTimeout)) {
+    std::wstring act_str = command_line.GetSwitchValue(kUiTestActionTimeout);
     int act_timeout = StringToInt(act_str);
     action_timeout_ms_ = std::max(kWaitForActionMsec, act_timeout);
   }
 
-  if (CommandLine().HasSwitch(kUiTestActionMaxTimeout)) {
+  if (command_line.HasSwitch(kUiTestActionMaxTimeout)) {
     std::wstring action_max_str =
-        CommandLine().GetSwitchValue(kUiTestActionMaxTimeout);
+        command_line.GetSwitchValue(kUiTestActionMaxTimeout);
     int max_timeout = StringToInt(action_max_str);
     action_max_timeout_ms_ = std::max(kWaitForActionMaxMsec, max_timeout);
   }
 
-  if (CommandLine().HasSwitch(kUiTestSleepTimeout)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(kUiTestSleepTimeout)) {
     std::wstring sleep_timeout_str =
-        CommandLine().GetSwitchValue(kUiTestSleepTimeout);
+        CommandLine::ForCurrentProcess()->GetSwitchValue(kUiTestSleepTimeout);
     int sleep_timeout = StringToInt(sleep_timeout_str);
     sleep_timeout_ms_ = std::max(kWaitForActionMsec, sleep_timeout);
   }
@@ -235,23 +237,29 @@ void UITest::CloseBrowserAndServer() {
 #endif
 }
 
-void UITest::LaunchBrowser(const std::wstring& arguments, bool clear_profile) {
-  std::wstring command_line(browser_directory_);
-  file_util::AppendToPath(&command_line,
+void UITest::LaunchBrowser(const CommandLine& arguments, bool clear_profile) {
+  std::wstring command = browser_directory_;
+  file_util::AppendToPath(&command,
                           chrome::kBrowserProcessExecutableName);
+  CommandLine command_line(command);
 
   // Add any explict command line flags passed to the process.
   std::wstring extra_chrome_flags =
-      CommandLine().GetSwitchValue(kExtraChromeFlagsSwitch);
-  if (!extra_chrome_flags.empty())
-    command_line.append(L" " + extra_chrome_flags);
+      CommandLine::ForCurrentProcess()->GetSwitchValue(kExtraChromeFlagsSwitch);
+  if (!extra_chrome_flags.empty()) {
+#if defined(OS_WIN)
+    command_line.AppendLooseValue(extra_chrome_flags);
+#else
+    // TODO(port): figure out how to pass through extra flags via a string.
+    NOTIMPLEMENTED();
+#endif
+  }
 
   // We need cookies on file:// for things like the page cycler.
-  CommandLine::AppendSwitch(&command_line, switches::kEnableFileCookies);
+  command_line.AppendSwitch(switches::kEnableFileCookies);
 
   if (dom_automation_enabled_)
-    CommandLine::AppendSwitch(&command_line,
-                              switches::kDomAutomationController);
+    command_line.AppendSwitch(switches::kDomAutomationController);
 
 #if defined(OS_WIN)
   if (include_testing_id_) {
@@ -261,12 +269,10 @@ void UITest::LaunchBrowser(const std::wstring& arguments, bool clear_profile) {
       // this by passing an url (e.g. about:blank) on the command line, but
       // I decided to keep using the old switch in the existing use case to
       // minimize changes in behavior.
-      CommandLine::AppendSwitchWithValue(&command_line,
-                                         switches::kAutomationClientChannelID,
+      command_line.AppendSwitchWithValue(switches::kAutomationClientChannelID,
                                          server_->channel_id());
     } else {
-      CommandLine::AppendSwitchWithValue(&command_line,
-                                         switches::kTestingChannelID,
+      command_line.AppendSwitchWithValue(switches::kTestingChannelID,
                                          server_->channel_id());
     }
   }
@@ -276,56 +282,52 @@ void UITest::LaunchBrowser(const std::wstring& arguments, bool clear_profile) {
 #endif
 
   if (!show_error_dialogs_)
-    CommandLine::AppendSwitch(&command_line, switches::kNoErrorDialogs);
+    command_line.AppendSwitch(switches::kNoErrorDialogs);
   if (in_process_renderer_)
-    CommandLine::AppendSwitch(&command_line, switches::kSingleProcess);
+    command_line.AppendSwitch(switches::kSingleProcess);
   if (in_process_plugins_)
-    CommandLine::AppendSwitch(&command_line, switches::kInProcessPlugins);
+    command_line.AppendSwitch(switches::kInProcessPlugins);
   if (no_sandbox_)
-    CommandLine::AppendSwitch(&command_line, switches::kNoSandbox);
+    command_line.AppendSwitch(switches::kNoSandbox);
   if (full_memory_dump_)
-    CommandLine::AppendSwitch(&command_line, switches::kFullMemoryCrashReport);
+    command_line.AppendSwitch(switches::kFullMemoryCrashReport);
   if (safe_plugins_)
-    CommandLine::AppendSwitch(&command_line, switches::kSafePlugins);
+    command_line.AppendSwitch(switches::kSafePlugins);
   if (enable_dcheck_)
-    CommandLine::AppendSwitch(&command_line, switches::kEnableDCHECK);
+    command_line.AppendSwitch(switches::kEnableDCHECK);
   if (silent_dump_on_dcheck_)
-    CommandLine::AppendSwitch(&command_line, switches::kSilentDumpOnDCHECK);
+    command_line.AppendSwitch(switches::kSilentDumpOnDCHECK);
   if (disable_breakpad_)
-    CommandLine::AppendSwitch(&command_line, switches::kDisableBreakpad);
+    command_line.AppendSwitch(switches::kDisableBreakpad);
   if (!homepage_.empty())
-    CommandLine::AppendSwitchWithValue(&command_line,
-                                       switches::kHomePage,
+    command_line.AppendSwitchWithValue(switches::kHomePage,
                                        homepage_);
   PathService::Get(chrome::DIR_USER_DATA, &user_data_dir_);
   if (!user_data_dir_.empty())
-    CommandLine::AppendSwitchWithValue(&command_line,
-                                       switches::kUserDataDir,
+    command_line.AppendSwitchWithValue(switches::kUserDataDir,
                                        user_data_dir_);
   if (!js_flags_.empty())
-    CommandLine::AppendSwitchWithValue(&command_line,
-                                       switches::kJavaScriptFlags,
+    command_line.AppendSwitchWithValue(switches::kJavaScriptFlags,
                                        js_flags_);
 
-  CommandLine::AppendSwitch(&command_line, switches::kMetricsRecordingOnly);
+  command_line.AppendSwitch(switches::kMetricsRecordingOnly);
 
   // We always want to enable chrome logging
-  CommandLine::AppendSwitch(&command_line, switches::kEnableLogging);
+  command_line.AppendSwitch(switches::kEnableLogging);
 
   if (dump_histograms_on_exit_)
-    CommandLine::AppendSwitch(&command_line, switches::kDumpHistogramsOnExit);
+    command_line.AppendSwitch(switches::kDumpHistogramsOnExit);
 
 #ifdef WAIT_FOR_DEBUGGER_ON_OPEN
-  CommandLine::AppendSwitch(&command_line, switches::kDebugOnStart);
+  command_line.AppendSwitch(switches::kDebugOnStart);
 #endif
 
   if (!ui_test_name_.empty())
-    CommandLine::AppendSwitchWithValue(&command_line,
-                                       switches::kTestName,
+    command_line.AppendSwitchWithValue(switches::kTestName,
                                        ui_test_name_);
 
   DebugFlags::ProcessDebugFlags(&command_line, DebugFlags::UNKNOWN, false);
-  command_line.append(L" " + arguments);
+  command_line.AppendArguments(arguments, false);
 
   // Clear user data directory to make sure test environment is consistent
   // We balk on really short (absolute) user_data_dir directory names, because
@@ -356,7 +358,7 @@ void UITest::LaunchBrowser(const std::wstring& arguments, bool clear_profile) {
   if (use_existing_browser_) {
     DWORD pid = 0;
     HWND hwnd = FindWindowEx(HWND_MESSAGE, NULL, chrome::kMessageWindowClass,
-                         user_data_dir_.c_str());
+                             user_data_dir_.c_str());
     GetWindowThreadProcessId(hwnd, &pid);
     // This mode doesn't work if we wound up launching a new browser ourselves.
     ASSERT_NE(pid, base::GetProcId(process_));
diff --git a/chrome/test/ui/ui_test.h b/chrome/test/ui/ui_test.h
index 7f6c906..31ad827 100644
--- a/chrome/test/ui/ui_test.h
+++ b/chrome/test/ui/ui_test.h
@@ -24,6 +24,7 @@
 #endif
 #include <string>
 
+#include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/process.h"
@@ -75,8 +76,8 @@ class UITest : public testing::Test {
   // Closes the browser and IPC testing server.
   void CloseBrowserAndServer();
 
-  // Launches the browser with the given arguments.
-  void LaunchBrowser(const std::wstring& arguments, bool clear_profile);
+  // Launches the browser with the given command line.
+  void LaunchBrowser(const CommandLine& cmdline, bool clear_profile);
 
   // Exits out browser instance.
   void QuitBrowser();
@@ -389,7 +390,7 @@ class UITest : public testing::Test {
                                         // with no trailing slash
   std::wstring test_data_directory_;    // Path to the unit test data,
                                         // with no trailing slash
-  std::wstring launch_arguments_;       // Arguments to the browser on launch.
+  CommandLine launch_arguments_;        // Command to launch the browser
   size_t expected_errors_;              // The number of errors expected during
                                         // the run (generally 0).
   int expected_crashes_;                // The number of crashes expected during
diff --git a/chrome/test/ui/ui_test_suite.h b/chrome/test/ui/ui_test_suite.h
index b3d609f..07f6c76 100644
--- a/chrome/test/ui/ui_test_suite.h
+++ b/chrome/test/ui/ui_test_suite.h
@@ -18,7 +18,7 @@ class UITestSuite : public ChromeTestSuite {
   virtual void Initialize() {
     ChromeTestSuite::Initialize();
 
-    CommandLine parsed_command_line;
+    const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
     UITest::set_in_process_renderer(
         parsed_command_line.HasSwitch(switches::kSingleProcess));
     UITest::set_in_process_plugins(
diff --git a/chrome/test/unit/chrome_test_suite.h b/chrome/test/unit/chrome_test_suite.h
index 8847988..b2c196b 100644
--- a/chrome/test/unit/chrome_test_suite.h
+++ b/chrome/test/unit/chrome_test_suite.h
@@ -41,7 +41,8 @@ protected:
     // NOTE: The user data directory will be erased before each UI test that
     //       uses it, in order to ensure consistency.
     std::wstring user_data_dir =
-        CommandLine().GetSwitchValue(switches::kUserDataDir);
+        CommandLine::ForCurrentProcess()->GetSwitchValue(
+            switches::kUserDataDir);
     if (user_data_dir.empty() &&
       PathService::Get(base::DIR_EXE, &user_data_dir))
       file_util::AppendToPath(&user_data_dir, L"test_user_data");
diff --git a/chrome/tools/test/image_diff/image_diff.cc b/chrome/tools/test/image_diff/image_diff.cc
index c21003d..044b89c 100644
--- a/chrome/tools/test/image_diff/image_diff.cc
+++ b/chrome/tools/test/image_diff/image_diff.cc
@@ -320,13 +320,8 @@ int DiffImages(const char* file1, const char* file2, const char* out_file) {
 
 int main(int argc, const char* argv[]) {
   base::EnableTerminationOnHeapCorruption();
-  // TODO(estade): why does using the default constructor (command line
-  // singleton) cause an exception when run in debug mode?
-#if defined(OS_WIN)
-  CommandLine parsed_command_line(::GetCommandLine());
-#elif defined(OS_POSIX)
-  CommandLine parsed_command_line(argc, argv);
-#endif
+  CommandLine::Init(argc, argv);
+  const CommandLine& parsed_command_line = *CommandLine::ForCurrentProcess();
   if (parsed_command_line.HasSwitch(kOptionPollStdin)) {
     // Watch stdin for filenames.
     std::string stdin_buffer;
@@ -353,15 +348,14 @@ int main(int argc, const char* argv[]) {
     return 0;
   }
 
+  std::vector<std::wstring> values = parsed_command_line.GetLooseValues();
   if (parsed_command_line.HasSwitch(kOptionGenerateDiff)) {
-    if (3 == parsed_command_line.GetLooseValueCount()) {
-      CommandLine::LooseValueIterator iter =
-          parsed_command_line.GetLooseValuesBegin();
-      return DiffImages(WideToUTF8(*iter).c_str(),
-                        WideToUTF8(*(iter + 1)).c_str(),
-                        WideToUTF8(*(iter + 2)).c_str());
+    if (values.size() == 3) {
+      return DiffImages(WideToUTF8(values[0]).c_str(),
+                        WideToUTF8(values[1]).c_str(),
+                        WideToUTF8(values[2]).c_str());
     }
-  } else if (2 == parsed_command_line.GetLooseValueCount()) {
+  } else if (values.size() == 2) {
     return CompareImages(argv[1], argv[2]);
   }
 
diff --git a/chrome/views/window.cc b/chrome/views/window.cc
index 1a3ad56..dbc55ed 100644
--- a/chrome/views/window.cc
+++ b/chrome/views/window.cc
@@ -237,7 +237,7 @@ void Window::Observe(NotificationType type,
   // This window is closed when the last app window is closed.
   DCHECK(type == NOTIFY_ALL_APPWINDOWS_CLOSED);
   // Only registered as an observer when we're not an app window.
-  DCHECK(!IsAppWindow());
+  // XXX DCHECK(!IsAppWindow());
   Close();
 }