Add --headless flag to Windows

chrome/app/chrome_main.cc

 // 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 <stdint.h>
 
 #include "base/command_line.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/app/chrome_main_delegate.h"
@@ skipping 88 matching lines @@
 
 #if defined(OS_LINUX) || defined(OS_MACOSX)
   if (command_line->HasSwitch(switches::kHeadless)) {
 #if defined(OS_MACOSX)
     SetUpBundleOverrides();
 #endif
     return headless::HeadlessShellMain(argc, argv);
   }
 #endif  // defined(OS_LINUX) || defined(OS_MACOSX)
 
+#if defined(OS_WIN)
+  base::CommandLine::Init(0, NULL);
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kHeadless)) {
+    return headless::HeadlessShellMain(instance, sandbox_info);
+  }
+#endif  // defined(OS_WIN)
+
 #if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
   version_info::Channel channel = chrome::GetChannel();
   if (channel == version_info::Channel::CANARY ||
       channel == version_info::Channel::UNKNOWN) {
     if (command_line->HasSwitch(switches::kMash))
       return MashMain();
     WaitForMashDebuggerIfNecessary();
     if (service_manager::ServiceManagerIsRemote())
       params.env_mode = aura::Env::Mode::MUS;
   }
 #endif  // BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
 
   int rv = content::ContentMain(params);
 
 #if defined(OS_WIN)
   base::win::SetShouldCrashOnProcessDetach(false);
 #endif
 
   return rv;
 }