Implement a runtime headless mode for Linux

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 "build/build_config.h"
+#include "base/command_line.h"
 #include "base/time/time.h"
 #include "chrome/app/chrome_main_delegate.h"
 #include "chrome/common/features.h"
 #include "content/public/app/content_main.h"
+#include "content/public/common/content_switches.h"
+#include "headless/app/headless_shell.h"
 
 #if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
-#include "base/command_line.h"
 #include "chrome/app/mash/mash_runner.h"
 #include "chrome/common/channel_info.h"
 #include "components/version_info/version_info.h"
 #endif
 
 #if defined(OS_WIN)
 #include "base/debug/dump_without_crashing.h"
 #include "base/win/win_util.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/install_static/install_details.h"
@@ skipping 26 matching lines @@
   // of them at the OS level (this is fixed in VS2015). We force off usage of
   // FMA3 instructions in the CRT to avoid using that path and hitting illegal
   // instructions when running on CPUs that support FMA3, but OSs that don't.
   // See http://crbug.com/436603.
   _set_FMA3_enable(0);
 #endif  // WIN && ARCH_CPU_X86_64
 
 #if defined(OS_WIN)
   install_static::InstallDetails::InitializeFromPrimaryModule(
       chrome::kChromeElfDllName);
+
+  const base::CommandLine command_line(argc, argv);
+#if defined(OS_LINUX)
+  if (command_line.HasSwitch(switches::kHeadless))
+    return HeadlessShellMain(argc, argv);
 #endif
 
   ChromeMainDelegate chrome_main_delegate(
       base::TimeTicks::FromInternalValue(exe_entry_point_ticks));
   content::ContentMainParams params(&chrome_main_delegate);
 
 #if defined(OS_WIN)
   // The process should crash when going through abnormal termination.
   base::win::SetShouldCrashOnProcessDetach(true);
   base::win::SetAbortBehaviorForCrashReporting();
@@ skipping 20 matching lines @@
 #endif
 
 #if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
 #if !defined(OS_WIN)
   base::CommandLine::Init(params.argc, params.argv);
 #endif
 
   version_info::Channel channel = chrome::GetChannel();
   if (channel == version_info::Channel::CANARY ||
       channel == version_info::Channel::UNKNOWN) {
-    const base::CommandLine& command_line =
-        *base::CommandLine::ForCurrentProcess();
     if (command_line.HasSwitch("mash"))
       return MashMain();
   }
 #endif  // BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
 
   int rv = content::ContentMain(params);
 
 #if defined(OS_WIN)
   base::win::SetShouldCrashOnProcessDetach(false);
 #endif
 
   return rv;
 }