Introduce --cancel-first-run and reduce the strength of --no-first-run.

chrome/browser/chrome_browser_main_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chrome_browser_main_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <sys/sysctl.h>
 
 #include "base/command_line.h"
@@ skipping 211 matching lines @@
     PathService::Get(chrome::FILE_RESOURCES_PACK, &resources_pack_path);
     ResourceBundle::GetSharedInstance().AddDataPackFromPath(
         resources_pack_path, ui::SCALE_FACTOR_NONE);
   }
 
   // This is a no-op if the KeystoneRegistration framework is not present.
   // The framework is only distributed with branded Google Chrome builds.
   [[KeystoneGlue defaultKeystoneGlue] registerWithKeystone];
 
   // Disk image installation is sort of a first-run task, so it shares the
-  // kNoFirstRun switch.
+  // no first run switches.
   //
   // This needs to be done after the resource bundle is initialized (for
   // access to localizations in the UI) and after Keystone is initialized
   // (because the installation may need to promote Keystone) but before the
   // app controller is set up (and thus before MainMenu.nib is loaded, because
   // the app controller assumes that a browser has been set up and will crash
   // upon receipt of certain notifications if no browser exists), before
   // anyone tries doing anything silly like firing off an import job, and
   // before anything creating preferences like Local State in order for the
   // relaunched installed application to still consider itself as first-run.
-  if (!parsed_command_line().HasSwitch(switches::kNoFirstRun)) {
+  if (!parsed_command_line().HasSwitch(switches::kCancelFirstRun) &&

[grt (UTC plus 2), 2013/07/30 02:48:16]

how about abstracting the tests for flags away into a helper:
  if (!first_run::IsFirstRunSuppressed(parsed_command_line())) {
    ...
  }

[gab, 2013/07/30 14:10:17]

Done.

+      !parsed_command_line().HasSwitch(switches::kSkipFirstRun)) {
     if (MaybeInstallFromDiskImage()) {
       // The application was installed and the installed copy has been
       // launched.  This process is now obsolete.  Exit.
       exit(0);
     }
   }
 
   // Now load the nib (from the right bundle).
   base::scoped_nsobject<NSNib> nib(
       [[NSNib alloc] initWithNibNamed:@"MainMenu"
@@ skipping 13 matching lines @@
 void ChromeBrowserMainPartsMac::PostProfileInit() {
   ChromeBrowserMainPartsPosix::PostProfileInit();
   g_browser_process->metrics_service()->RecordBreakpadRegistration(
       IsCrashReporterEnabled());
 }
 
 void ChromeBrowserMainPartsMac::DidEndMainMessageLoop() {
   AppController* appController = [NSApp delegate];
   [appController didEndMainMessageLoop];
 }